Compounds which are used in the preparation of the compound of formula (II)

ABSTRACT

This invention relates to compounds which are used in the preparation of the compound of formula (II).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of co-pending U.S. Non-Provisional application Ser. No. 16/129,322 filed Sep. 12, 2018, which is a Continuation of U.S. Non-Provisional application Ser. No. 15/298,431 filed Oct. 20, 2016, which in turn, is a Continuation-In Part of PCT Application No. PCT/GB2015/053731, filed Dec. 4, 2015, which in turn, claims priority from European Application No. 14196662.2, filed Dec. 5, 2014. Applicant claims the benefits of 35 U.S.C. § 120 as to the PCT application and priority under 35 U.S.C. § 119 as to the said European application, and the entire disclosures of all applications are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

This invention relates to a compound useful in the treatment of mycoses, compositions containing it and its use in therapy.

BACKGROUND OF THE INVENTION

The incidence of fungal infections has increased substantially over the past two decades and invasive forms are leading causes of morbidity and mortality, especially amongst immunocompromised or immunosuppressed patients. Disseminated candidiasis, pulmonary aspergillosis, and emerging opportunistic fungi are the most common agents producing these serious mycoses. It is a particular feature of fungi that they are able to generate an extracellular matrix (ECM) that binds them together and allows them to adhere to their in vitro or in vivo substrates. These biofilms serve to protect them against the hostile environments of the host immune system and to resist antimicrobial killing (Kaur and Singh, 2013).

Pulmonary aspergillosis can be segmented into those patients suffering with non-invasive disease versus those with an invasive condition. A further sub-division is used to characterise patients who exhibit an allergic component to aspergillosis (known as ABPA; allergic bronchopulmonary aspergillosis) compared with those that do not. The factors precipitating pulmonary aspergillosis may be acute, such as exposure to high doses of immuno-suppressive medicines or to intubation in an intensive care unit. Alternatively, they may be chronic, such as a previous infection with TB (Denning et al., 2011a). Chronic lung infections with Aspergillus can leave patients with extensive and permanent lung damage, requiring lifetime treatment with oral azole drugs (Limper et al., 2011).

A growing body of research suggests that Aspergillus infection may play an important role in clinical asthma (Chishimba et al., 2012; Pasqualotto et al., 2009). Furthermore, recently published work has correlated Aspergillus infection with poorer clinical outcomes in patients with COPD (Bafadhel et al., 2013). Similarly cross-sectional studies have shown associations between the presence of Aspergillus spp. and Candida spp. in the sputum and worsened lung function (Chotirmall et al., 2010; Agbetile et al., 2012).

Invasive aspergillosis (IA) exhibits high mortality rates in immunocompromised patients, for example, those undergoing allogenic stem cell transplantation or solid organ transplants (such as lung transplants). The first case of IA reported in an immunocompromised patient occurred in 1953. This event was concurrent with the introduction of corticosteroids and cytotoxic chemotherapy into treatment regimens (Rankin, 1953). Invasive aspergillosis is a major concern in the treatment of leukaemia and other haematological malignancies given its high incidence and associated mortality. Death rates usually exceed 50% (Lin et al., 2001) and long term rates can reach 90% in allogeneic hematopoietic stem cell transplantation recipients, despite the availiability of oral triazole medicines (Salmeron et al., 2012). In patients undergoing solid organ transplantation (particularly of the lung), the use of high doses of steroids leaves patients vulnerable to infection (Thompson and Patterson, 2008) which is a serious problem. The disease has also appeared in less severely immunocompromised patient populations. These include those suffering with underlying COPD or cirrhosis, patients receiving high dose steroids, and individuals fitted with central venous catheters or supported by mechanical ventilation (Dimopoulos et al., 2012).

Existing anti-fungal medicines are predominantly dosed either orally or systemically. These commonly exploited routes of delivery are poor for treating lung airways infections, since drug concentrations achieved at the site of infection tend to be lower than those in organs. This is especially so for the liver, which is a site of toxicity: up to 15% of patients treated with voriconazole suffer raised transaminase levels (Levin et al., 2007; Lat and Thompson, 2011). Exposure of the liver also results in significant drug interactions arising from the the inhibition of hepatic P450 enzymes (Jeong, et al., 2009; Wexler et al., 2004).

Furthermore, the widespread use of triazoles, both in the clinic and in agriculture has led to a growing and problematic emergence of resistant mycoses in some locations (Denning et al., 2011b; Bowyer and Denning, 2014).

It is clearly evident that an urgent medical need exists for novel anti-fungal medicines that deliver improved efficacy and better systemic tolerability profiles.

SUMMARY OF THE INVENTION

In a first aspect, the invention provides Compound (I)

which is: 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydro furan-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)-N-(4-fluorophenyl)benzamide, and pharmaceutically acceptable salts thereof (hereinafter sometimes referred to as the “compound of the invention”).

Biological data disclosed herein below reveals that the compound of the invention, Compound (I), is a potent inhibitor of Aspergillus fumigatus growth in in vitro assays. In immunosuppressed mice Compound (I) demonstrated potent inhibition of Aspergillus fumigatus infections. Other desirable properties of Compound (I) are described herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 displays the effects of prophylactic and therapeutic treatment with Compound (I) on CFU in lung of Aspergillus fumigatus infected, immuno-compromised, neutropenic mice.

FIG. 2 and FIG. 3 show the effects of prophylactic and therapeutic treatment with Compound (I) on galactomannan concentrations in BALF and serum respectively, in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice.

In FIGS. 1-3, the symbol *** indicates significance with P<0.001.

DETAILED DESCRIPTION OF THE INVENTION

Three alternative, convergent routes which have been developed for the generation of Compound (I) from commercially available starting materials are depicted above (Scheme 1).

These synthetic methodologies differ in the manner in which the advanced benzoate ester intermediates of formula (IV) are prepared.

Route 1

The Buchwald coupling of a suitably protected piperazine derivative (XII) with 4-bromo-2-methylphenol (XIVa) under conditions typically employed for such reactions provides the mono N-arylated piperazine (XI). A suitable nitrogen protective group for such transformations is as a urethane, using a Boc group (P=CO₂ ^(t)Bu). Those skilled in the art will appreciate that a wide variety of conditions may be used for affecting transformations of this kind. In particular, palladium catalysts and phosphine ligands such as RuPhosG3 and RuPhos are routinely employed in the presence of a base, for example, cesium carbonate or lithium hexamethyldisilazide. Alkylation of the resulting phenol (XI), under basic conditions, with the tosylate (IX) generates the ether (VII). The tosylate (IX) is a configurationally stable, non-volatile (solid) reagent that is widely available, in high enantiomeric purity, from commercial sources; though other electrophilic derivatives such as the corresponding mesylate, as well as the halomethyl (e.g. chloromethyl and bromomethyl) derivatives would be anticipated as suitable alternatives for this transformation. Removal of the nitrogen protective group reveals the mono-substituted piperazine (V). In the case of a Boc derivative (R^(b)=CO₂ ^(t)Bu), the amine deprotection step is typically undertaken by exposure of the carbamate to strong mineral acid or a strong organic acid, such as TFA, either neat or in the presence of a solvent, such as DCM. A second Buchwald coupling of the amine (V) with an alkyl 4-bromobenzoate (VI), under basic conditions and the agency of a catalyst, gives rise to the N,N′-bisarylated product (IV) in which R^(a) represents lower alkyl, such as C₁₋₅ alkyl, for example methyl or ethyl, or else terf-butyl.

Route 2

The benzoate ester intermediates (IV), may be obtained in an alternative process in which only a single palladium-mediated coupling is required. Reaction of the bromophenol (XIVa) with a mono N-arylated piperazine derivative [(X), R^(a)=lower alkyl, such as C₁₋₅ alkyl, for example methyl or ethyl, or else tert-butyl], under standard Buchwald coupling conditions, gives rise to a 1,4-bisarylpiperazine (VIII). The O-alkylation of this phenolic product, with the tosylate (IX), as described above, provides the ether products (IV) directly, in two steps, from commercially available starting materials.

Route 3

It will be appreciated from the preparative routes outlined above (Scheme 1) that in some instances it is advantageous to perform the same or similar synthetic transformations in a different order, so as to improve the overall efficiency of the processes and/or the quality of the materials obtained therefrom. For example, the bromophenol (XIVa) may be transformed into the compounds of formula (IV) by conducting the two steps, outlined above, in reverse order. In this manner, treatment of the said phenol with the tosylate (IX) provides the ether derivatives of formula (XIII). This aryl bromide substrate may be reacted with an N-aryl piperazine of formula (X), under Buchwald coupling conditions as previously described, to provide the intermediates of formula (IV),

Preparation of Compound (I) from Intermediate (IV)

In some cases, for example those in which R^(a) is methyl or ethyl, generation of the free benzoic acid (II) is conveniently undertaken by treatment of the ester (IV) with a base in the presence of water. Typical conditions include treatment with an alkali metal hydroxide, such as lithium hydroxide, in a mixture of water and a suitable aq miscible solvent. In other instances, as in the case of a tert-butyl ester, it may be advantageous to conduct the hydrolysis step under acidic conditions. Common reagents for such interconversions include strong inorganic acids, for example hydrochloric acid, in the presence of a water miscible, organic solvent such as IPA.

Treatment of the benzoic acid product (II), with 4-fluoroaniline under standard amide coupling conditions, widely available in the art, provides the compound of the invention, Compound (I). For example the reaction may be undertaken by mixing the acid (II) and 4-fluoroaniline with the coupling agents HOBt and EDCI in a polar, non protic solvent such as DMF in the presence of a non-nucleophilic organic base, typically DIPEA and the like.

Route 4

The compound of the present invention may also be assembled using yet another variation of the preparative technologies described herein (Scheme 2). In this alternative process (Route 4) amide bond formation is undertaken as the first step and generation of the ether linkage constitutes the last synthetic transformation. Acylation of 4-fluoroaniline (11) with 4-bromobenzoyl chloride (XX) provides the anilide fragment (XIX). As already noted such amidic products may be prepared from the corresponding amine and benzoic acid directly using a variety of activating agents, including peptide coupling reagents, of which a wide choice is available in the art. Subjecting the aryl bromide product to the Buchwald coupling conditions, with a suitable mono-protected piperazine (XII), under the agency of a catalyst in the manner recorded above, gives rise to the intermediates of formula (XVIII). In the case of a Boc protective group [P=CO₂ ^(t)Bu] the desired N-aryl piperazine (XVII) is readily obtained by brief exposure to a strong acid, for example, by treatment with TFA, which is then conveniently removed from the reaction medium by evaporation under reduced pressure. The phenolic precursor to compound (I), [(XV); R^(c)=H], was then derived in two steps from a second Buchwald coupling with the bromo-anisole (XIVb), to give the methyl ether intermediate [(XVI) R^(c)=Me], followed by an O-dealkylation with boron tribromide. The phenol (XV) was then converted into Compound (I), by re-alkylation with the tosylate reagent (IX) in the manner previously described.

Protective groups and the means for their removal are described in “Protective Groups in Organic Synthesis”, by Theodora W. Greene and Peter G. M. Wuts, published by John Wiley & Sons Inc; 4th Rev Ed., 2006, ISBN-10: 0471697540. A review of methodologies for the preparation of amides is covered in: “Amide bond formation and peptide coupling” Montalbetti, C. A. G. N. and Falque, V. Tetrahedron, 2005, 61, 10827-10852.

Thus the invention also provides a process for preparing Compound (I) or a pharmaceutically acceptable salt thereof which comprises reacting a compound of formula (II):

-   -   wherein:         -   R^(a) represents hydrogen;

or an activated derivative thereof (such as an acid halide e.g. an acid chloride or an acid anhydride); or a salt thereof;

with a compound of formula (III):

-   -   or a salt thereof.

The invention also provides a process for preparing Compound (I) or a pharmaceutically acceptable salt thereof which comprises reacting a compound of formula (XV):

or a salt thereof;

with a compound of formula (IX):

-   -   wherein:         -   Z represents a leaving group such as p-TolylSO₂O;

or a salt thereof.

Pharmaceutically acceptable salts of compounds of formula (I) include in particular pharmaceutically acceptable acid addition salts of said compounds. The pharmaceutically acceptable acid addition salts of compounds of formula (I) are meant to comprise the therapeutically active non-toxic acid addition salts that the compounds of formula (I) are able to form. These pharmaceutically acceptable acid addition salts can conveniently be obtained by treating the free base form with such appropriate acids in a suitable solvent or mixture of solvents. Appropriate acids comprise, for example, inorganic acids such as hydrohalic acids, e.g. hydrochloric or hydrobromic acid, sulfuric, nitric, phosphoric acids and the like; or organic acids such as, for example, acetic, propanoic, hydroxyacetic, lactic, pyruvic, malonic, succinic, maleic, fumaric, malic, tartaric, citric, methanesulfonic, ethanesulfonic, benzenesulfonic, p-toluenesulfonic, cyclamic, salicylic, p-aminosalicylic, pamoic acid and the like.

Conversely said salt forms can be converted by treatment with an appropriate base into the free base form.

The definition of the compound of formula (I) is intended to include all tautomers of said compound.

The definition of the compound of formula (I) is intended to include all solvates of said compound (including solvates of salts of said compound) unless the context specifically indicates otherwise. Examples of solvates include hydrates.

The compound of the disclosure includes embodiments wherein one or more atoms specified are naturally occurring or non-naturally occurring isotopes. In one embodiment the isotope is a stable isotope. Thus the compounds of the disclosure include, for example deuterium containing compounds and the like.

The disclosure also extends to all polymorphic forms of the compound herein defined. Novel intermediates, as described herein, of formula (II), (IV), (V), (VII), (VIII), (XIII) and (XV) and salts thereof, form a further aspect of the invention. Salts include pharmaceutically acceptable salts (such as those mentioned above) and non-pharmaceutically acceptable salts.

Salts of acids (e.g. carboxylic acids) include first and second group metal salts including sodium, potassium, magnesium and calcium salts.

In an embodiment there is provided a pharmaceutical composition comprising the compound of the invention optionally in combination with one or more pharmaceutically acceptable diluents or carriers.

Suitably the compound of the invention is administered topically to the lung or nose, particularly, topically to the lung. Thus, in an embodiment there is provided a pharmaceutical composition comprising the compound of the invention optionally in combination with one or more topically acceptable diluents or carriers.

Suitable compositions for pulmonary or intranasal administration include powders, liquid solutions, liquid suspensions, nasal drops comprising solutions or suspensions or pressurised or non-pressurised aerosols.

The compositions may conveniently be administered in unit dosage form and may be prepared by any of the methods well-known in the pharmaceutical art, for example as described in Remington's Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., (1985). The compositions may also conveniently be administered in multiple unit dosage form.

Topical administration to the nose or lung may be achieved by use of a non-pressurised formulation such as an aqueous solution or suspension. Such formulations may be administered by means of a nebuliser e.g. one that can be hand-held and portable or for home or hospital use (i.e. non-portable). An example device is a RESPIMAT inhaler. The formulation may comprise excipients such as water, buffers, tonicity adjusting agents, pH adjusting agents, viscosity modifiers, surfactants and co-solvents (such as ethanol). Suspension liquid and aerosol formulations (whether pressurised or unpressurised) will typically contain the compound of the invention in finely divided form, for example with a D₅₀ of 0.5-10 μm e.g. around 1-5 μm. Particle size distributions may be represented using D₁₀, D₅₀ and D₉₀ values. The D₅₀ median value of particle size distributions is defined as the particle size in microns that divides the distribution in half. The measurement derived from laser diffraction is more accurately described as a volume distribution, and consequently the D₅₀ value obtained using this procedure is more meaningfully referred to as a Dv₅₀ value (median for a volume distribution). As used herein Dv values refer to particle size distributions measured using laser diffraction. Similarly, D₁₀ and D₉₀ values, used in the context of laser diffraction, are taken to mean Dv₁₀ and Dv₉₀ values and refer to the particle size whereby 10% of the distribution lies below the D₁₀ value, and 90% of the distribution lies below the D₉₀ value, respectively.

According to one specific aspect of the invention there is provided a pharmaceutical composition comprising the compound of the invention in particulate form suspended in an aqueous medium. The aqueous medium typically comprises water and one or more excipients selected from buffers, tonicity adjusting agents, pH adjusting agents, viscosity modifiers and surfactants.

Topical administration to the nose or lung may also be achieved by use of an aerosol formulation. Aerosol formulations typically comprise the active ingredient suspended or dissolved in a suitable aerosol propellant, such as a chlorofluorocarbon (CFC) or a hydrofluorocarbon (HFC). Suitable CFC propellants include trichloromonofluoromethane (propellant 11), dichlorotetrafluoromethane (propellant 114), and dichlorodifluoromethane (propellant 12). Suitable HFC propellants include tetrafluoroethane (HFC-134a) and heptafluoropropane (HFC-227). The propellant typically comprises 40%-99.5% e.g. 40%-90% by weight of the total inhalation composition. The formulation may comprise excipients including co-solvents (e.g. ethanol) and surfactants (e.g. lecithin, sorbitan trioleate and the like). Other possible excipients include polyethylene glycol, polyvinylpyrrolidone, glycerine and the like. Aerosol formulations are packaged in canisters and a suitable dose is delivered by means of a metering valve (e.g. as supplied by Bespak, Valois or 3M or alternatively by Aptar, Coster or Vari).

Topical administration to the lung may also be achieved by use of a dry-powder formulation. A dry powder formulation will contain the compound of the disclosure in finely divided form, typically with an MMD of 1-10 μm or a D₅₀ of 0.5-10 μm e.g. around 1-5 μm. Powders of the compound of the invention in finely divided form may be prepared by a micronization process or similar size reduction process. Micronization may be performed using a jet mill such as those manufactured by Hosokawa Alpine. The resultant particle size distribution may be measured using laser diffraction (e.g. with a Malvern Mastersizer 2000S instrument). The formulation will typically contain a topically acceptable diluent such as lactose, glucose or mannitol (preferably lactose), usually of comparatively large particle size e.g. an MMD of 50 μm or more, e.g. 100 μm or more or a D₅₀ of 40-150 μm. As used herein, the term “lactose” refers to a lactose-containing component, including α-lactose monohydrate, β-lactose monohydrate, α-lactose anhydrous, β-lactose anhydrous and amorphous lactose. Lactose components may be processed by micronization, sieving, milling, compression, agglomeration or spray drying. Commercially available forms of lactose in various forms are also encompassed, for example Lactohale® (inhalation grade lactose; DFE Pharma), InhaLac®70 (sieved lactose for dry powder inhaler; Meggle), Pharmatose® (DFE Pharma) and Respitose® (sieved inhalation grade lactose; DFE Pharma) products. In one embodiment, the lactose component is selected from the group consisting of α-lactose monohydrate, α-lactose anhydrous and amorphous lactose. Preferably, the lactose is α-lactose monohydrate.

Dry powder formulations may also contain other excipients such as sodium stearate, calcium stearate or magnesium stearate.

A dry powder formulation is typically delivered using a dry powder inhaler (DPI) device. Example dry powder delivery systems include SPINHALER, DISKHALER, TURBOHALER, DISKUS, SKYEHALER, ACCUHALER and CLICKHALER. Further examples of dry powder delivery systems include ECLIPSE, NEXT, ROTAHALER, HANDIHALER, AEROLISER, CYCLOHALER, BREEZHALER/NEOHALER, MONODOSE, FLOWCAPS, TWINCAPS, X-CAPS, TURBOSPIN, ELPENHALER, MIATHALER, TWISTHALER, NOVOLIZER, PRESSAIR, ELLIPTA, ORIEL dry powder inhaler, MICRODOSE, PULVINAL, EASYHALER, ULTRAHALER, TAIFUN, PULMOJET, OMNIHALER, GYROHALER, TAPER, CONIX, XCELOVAIR and PROHALER.

The compound of the invention might also be administered topically to another internal or external surface (e.g. a mucosal surface or skin) or administered orally. The compound of the invention may be formulated conventionally for such routes of administration.

The compound of the invention is useful in the treatment of mycoses and for the prevention or treatment of disease associated with mycoses.

In an aspect of the invention there is provided use of the compound of the invention in the manufacture of a medicament for the treatment of mycoses and for the prevention or treatment of disease associated with mycoses.

In another aspect of the invention there is provided a method of treatment of a subject with a mycosis which comprises administering to said subject an effective amount of the compound of the invention.

In another aspect of the invention there is provided a method of prevention or treatment of disease associated with a mycosis in a subject which comprises administering to said subject an effective amount of the compound of the invention.

Mycoses may, in particular, be caused by Aspergillus spp. such as Aspergillus fumigatus or Aspergillus pullulans especially Aspergillus fumigatus Mycoses may also be caused by Candida spp. e.g. Candida albicans or Candida glabrata, Rhizopus spp. e.g. Rhizopus oryzae, Cryptococcus spp. e.g. Cryptococcus neoformans, Chaetomium spp. e.g. Chaetomium globosum, Penicillium spp. e.g. Penicillium chrysogenum and Trichophyton spp. e.g. Trichophyton rubrum.

A disease associated with a mycosis is, for example, pulmonary aspergillosis.

The compound of the invention may be used in a prophylactic setting by administering the said compound prior to onset of the mycosis.

Subjects include human and animal subjects, especially human subjects.

The compound of the invention is especially useful for the treatment of mycoses such as Aspergillus fumigatus infection and for the prevention or treatment of disease associated with mycoses such as Aspergillus fumigatus infection in at risk subjects. At risk subjects include premature infants, children with congenital defects of the lung or heart, immunocompromised subjects (e.g. those suffering from HIV infection), asthmatics, subjects with cystic fibrosis, elderly subjects and subjects suffering from a chronic health condition affecting the heart or lung (e.g. congestive heart failure or chronic obstructive pulmonary disease).

The compound of the invention is also useful for the treatment of azole resistant mycoses such as azole resistant Aspergillus fumigatus infection, particularly in combination with posaconazole.

The compound of the invention may be administered in combination with a second or further active ingredient. Second or further active ingredients may, for example, be selected from other anti-fungal agents (such as voriconazole or posaconazole), amphotericin B, an echinocandin (such as caspofungin) and an inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA reductase (such as lovastatin, pravastatin or fluvastatin).

Second or further active ingredients include active ingredients suitable for the treatment or prevention of a mycosis such as Aspergillus fumigatus infection or disease associated with a mycosis such as Aspergillus fumigatus infection or conditions co-morbid with a mycosis such as Aspergillus fumigatus infection.

The compound of the invention may be co-formulated with a second or further active ingredient or the second or further active ingredient may be formulated to be administered separately by the same or a different route.

For example, the compound of the invention may be administered to patients already being treated systemically with an anti-fungal, such as voriconazole or posaconazole.

For example, the compound of the invention may be co-administered e.g. co-formulated with one or more agents selected from amphotericin B, an echinocandin, such as caspofungin, and an inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA reductase, such as lovastatin, pravastatin or fluvastatin.

The compound of the invention may alternatively (or in addition) be co-administered e.g. co-formulated with one or more agents selected from candicidin, filipin, hamycin, natamycin, nystatin, rimocidin, bifonazole, butoconazole, clotrimazole, econazole, fenticonazole, isoconazole, ketoconazole, luliconazole, miconazole, omoconazole, oxiconazole. sertaconazole, sulconazole, tioconazole, albaconazole, efinaconazole, epoxiconazole, fluconazole, isavuconazole, itraconazole, propiconazole, ravuconazole, terconazole, abafungin, amorolfin, butenafine, naftifine, terbinafine, anidulafungin, micafungin, benzoic acid, ciclopirox, flucytosine (5-fluorocytosine), griseofulvin, tolnaftate and undecylenic acid.

Preferred combination partners include intraconazole, voriconazole, caspofungin and posaconazole.

According to an aspect of the invention there is provided a kit of parts comprising (a) a pharmaceutical composition comprising the compound of the invention optionally in combination with one or more diluents or carriers; (b) a pharmaceutical composition comprising a second active ingredient optionally in combination with one or more diluents or carriers; (c) optionally one or more further pharmaceutical compositions each comprising a third or further active ingredient optionally in combination with one or more diluents or carriers; and (d) instructions for the administration of the pharmaceutical compositions to a subject in need thereof. The subject in need thereof may suffer from or be susceptible to a mycosis such as Aspergillus fumigatus infection.

The compound of the invention may be administered at a suitable interval, for example once per day, twice per day, three times per day or four times per day.

A suitable dose amount for a human of average weight (50-70 kg) is expected to be around 50 μg to 10 mg/day e.g. 500 μg to 5 mg/day although the precise dose to be administered may be determined by a skilled person.

The compound of the invention is expected to have one or more of the following favourable attributes:

-   -   potent antifungal activity, particularly activity against         Aspergillus spp. such as Aspergillus fumigatus or activity         against Candida spp. e.g. Candida albicans or Candida glabrata,         Rhizopus spp. e.g. Rhizopus oryzae, Cryptococcus spp. e.g.         Cryptococcus neoformans, Chaetomium spp. e.g. Chaetomium         globosum, Penicillium spp. e.g. Penicillium chrysogenum or         Trichophyton spp. e.g. Trichophyton rubrum, especially following         topical administration to the lung or nose;     -   long duration of action in lungs, preferably consistent with         once daily dosing;     -   low systemic exposure following topical administration to the         lung or nose; and     -   an acceptable safety profile, especially following topical         administration to the lung or nose.

EXPERIMENTAL SECTION

Abbreviations used herein are defined below (Table 1). Any abbreviations not defined are intended to convey their generally accepted meaning.

TABLE 1 Abbreviations ABPA allergic bronchopulmonary aspergillosis aq aqueous ATCC American Type Culture Collection BALF bronchoalveolar lavage fluid BEAS2B SV40-immortalised human bronchial epithelial cell line Boc tert-butyloxycarbonyl br broad BSA bovine serum albumin CC₅₀ 50% cell cytotoxicity concentration CFU colony forming unit(s) CLSI Clinical and Laboratory Standards Institute COI cut off index conc concentration/concentrated d doublet DCM dichloromethane DFB₅₀ days taken to reach a fungal burden of 50% of control DIPEA N,N-diisopropylethylamine DMAP 4-dimethylaminopyridine DMEM Dulbecco's Modified Eagle Medium DMF N,N-dimethylformamide DMSO dimethyl sulfoxide DSS dextran sodium sulphate EBM endothelial basal media ECM extracellular matrix EDCl•HCl N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride EGM2 endothelial cell growth media 2 EUCAST European Committee on Antimicrobial Susceptibility Testing (ES⁺) electrospray ionization, positive mode Et ethyl Et₃N triethylamine EtOAc ethyl acetate FBS foetal bovine serum GM galactomannan HPAEC human pulmonary artery endothelial cell HOBt•H₂O 1-hydroxybenzotriazole mono-hydrate HPLC reverse phase high performance liquid chromatography hr hour(s) IA invasive aspergillosis i.n. intranasal IPA 2-propanol i.t. intra-tracheal LC-MS liquid chromatography-mass spectrometry Li Hep lithium heparin LiHMDS lithium bis(trimethylsilyl)amide m multiplet (M + H)⁺ protonated molecular ion MDA malondialdehyde Me methyl MeCN acetonitrile MeOH methanol MHz megahertz MIC₅₀ 50% of minimum inhibitory concentration MIC₇₃ 75% of minimum inhibitory concentration MIC₉₀ 90% of minimum inhibitory concentration min minute(s) MMD mass median diameter MOI multiplicity of infection MOPS 3-(N-morpholino)propanesulfonic acid m/z: mass-to-charge ratio NCPF National Collection of Pathogenic Fungi NMR nuclear magnetic resonance (spectroscopy) NT not tested OD optical density PBS phosphate buffered saline P protective group q quartet RT room temperature RP HPLC reverse phase high performance liquid chromatography RPMI Roswell Park Memorial Institute medium RuPhos 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl RuPhosG3 (2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl)[2- (2′-amino-1,1′-biphenyl)]palladium (II)methanesulfonate s singlet sat saturated sc sub-cutaneous SDS sodium dodecyl sulphate t triplet TFA trifluoroactic acid THF tetrahydrofuran TR34/L98H An Aspergillus fumigatus strain containing a leucine- to-histidine substitution at codon 98 and a 34-bp tandem repeat

General Procedures

All starting materials and solvents were obtained either from commercial sources or prepared according to the literature citation. Unless otherwise stated all reactions were stirred. Organic solutions were routinely dried over anhydrous magnesium sulfate.

Analytical Methods

Reverse Phase HPLC Methods:

Waters Xselect CSH C18 XP column, 2.5 μm (4.6×30 mm) at 40° C.; flow rate 2.5-4.5 mL min⁻¹ eluted with a H₂O-MeCN gradient containing either 0.1% v/v formic acid (Method a) or 10 mM NH₄HCO₃ in water (Method b) over 4 min employing UV detection at 254 nm. Gradient information: 0-3.00 min, ramped from 95% H₂O-5% MeCN to 5% H₂O-95% MeCN; 3.00-3.01 min, held at 5% H₂O-95% MeCN, flow rate increased to 4.5 mL min⁻¹; 3.01 3.50 min, held at 5% H₂O-95% MeCN; 3.50-3.60 min, returned to 95% H₂O-5% MeCN, flow rate reduced to 3.50 mL min⁻¹; 3.60-3.90 min, held at 95% H₂O-5% MeCN; 3.90-4.00 min, held at 95% H₂O-5% MeCN, flow rate reduced to 2.5 mL min⁻¹.

¹H NMR Spectroscopy:

¹H NMR spectra were acquired on a Bruker Advance III spectrometer at 400 MHz using residual undeuterated solvent as reference and unless specified otherwise were run in DMSO-d₆.

Synthetic Methods for the Preparation of Compound (I)

tert-butyl 4-(4-hydroxy-3-methylphenyl)piperazine-1-carboxylate.

A flask charged with tert-butylpiperazin-1-carboxylate (XIIa) (7.44 g, 40.0 mmol), 4-bromo-2-methylphenol (6.23 g, 33.3 mmol), RuPhos (311 mg, 0.67 mmol) and RuPhos G3 (557 mg, 0.67 mmol) was evacuated and backfilled with nitrogen three times. A solution of LiHMDS (1M in THF, 100 mL, 100 mmol) was added and the reaction mixture was heated at 70° C. for 3 hr. After cooling to RT the mixture was quenched by the addition of 1M hydrochloric acid (100 mL) and was then neutralised with 1 M aq. NaHCO₃ (100 mL). The aq layer was extracted with EtOAc (3×100 mL) and the combined organic extracts were dried. The volatiles were removed in vacuo to give a crude product which was purified by flash column chromatography (SiO₂, 120 g, 0-100% EtOAc in isohexanes, gradient elution) to afford the title compound, intermediate (XIa), as a light brown solid (7.80 g, 78%); R^(t) 2.07 min (Method b); m/z 293 (M+H)⁺ (ES⁺); ¹H NMR δ: 1.41 (9H, s), 2.07 (3H, s), 2.86-2.88 (4H, m), 3.41-3.43 (4H, m), 6.58-6.65 (2H, m), 6.71 (1H, d) and 8.72 (1H, s).

1-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazine

To a solution of intermediate (XIa) (7.80 g, 25.1 mmol) in DMSO (60 mL) was added aq sodium hydroxide (3.0 mL, 12.5 M, 37.6 mmol). The mixture was stirred at RT for 10 min and was then treated portionwise with ((3S,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluoro phenyl)tetrahydrofuran-3-yl)methyl4-methylbenzenesulfonate (IX) (ex APIChem, Catalogue Number: AC-8330, 12.4 g, 27.6 mmol). The reaction mixture was stirred at 30° C. for 18 hr, cooled to RT and water (200 mL) was added. The resulting mixture was extracted with EtOAc (3×200 mL) and the combined organic extracts were washed with brine (2×200 mL), and then dried and evaporated in vacuo to afford a brown oil. Analysis of the crude, Boc-protected product (VIIa) by ¹H NMR indicated that it contained ˜10% of the alkene: (R)-1-((2-(2,4-difluorophenyl)-4-methylenetetrahydrofuran-2-yl)methyl)-1H-1,2,4-triazole, formed as an elimination by-product. The crude urethane (VIIa) was taken up into DCM (150 mL) and treated with TFA (39.0 mL, 502 mmol). After 2 hr at RT the reaction mixture was concentrated in vacuo to remove most of the volatiles and was then diluted with EtOAc (200 mL) and washed with aq. NaOH (2 M, 200 mL). The aq phase was separated and was extracted with EtOAc (2×200 mL). The combined organic extracts were washed with brine (2×200 mL) and then dried and evaporated in vacuo to afford a light brown oil. The crude product was purified by flash column chromatography (SiO₂, 80 g, 0-10% 0.7 M NH₃/MeOH in DCM, gradient elution) to afford the title compound, intermediate (V), as a viscous, light brown oil (9.46 g, 80%); R^(t) 1.91 min (Method b); m/z 470 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.07 (3H, s), 2.15 (1H, dd), 2.36-2.42 (1H, m), 2.52-2.56 (1H, m), 2.79-2.81 (4H, m), 2.87-2.90 (4H, m), 3.66 (1H, dd), 3.73-3.77 (2H, m), 4.04 (1H, t), 4.57 (2H, dd), 6.64 (1H, dd), 6.70-6.75 (2H, m), 6.99 (1H, td), 7.25-7.34 (2H, m), 7.76 (1H, s) and 8.34 (1H, s).

Methyl 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetra hydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoate

A flask charged with intermediate (V) (9.00 g, 19.2 mmol), methyl-4-bromobenzoate (Via) (4.95 g, 23.0 mmol), RuPhos (0.18 g, 0.38 mmol, 2 mol %), RuPhosG3 (0.32 g, 0.38 mmol, 2 mol %) and cesium carbonate (9.99 g, 30.7 mmol) was evacuated and refilled with nitrogen three times before DMF (150 mL) was added. The mixture was heated at 80° C. for 22 hr and then, whilst still hot, was poured into water (150 mL) to form a brown gum. More water (300 mL) was added and the aq. phase was extracted with DCM (2×200 mL). The organic extracts were combined and concentrated in vacuo to give a brown oil which was poured into water (100 mL). The resulting precipitate was collected by filtration and then re-suspended in THF (100 mL). The mixture was heated at reflux for 1 hr during which time a cream suspension was formed. The mixture was cooled to RT and the resulting precipitate was collected by filtration, washed with THF (2×50 mL) and then dried in vacuo to afford the title compound, intermediate (IVa), as a light yellow solid (9.48 g, 79%); R^(t) 2.79 min (Method b); m/z 604 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.09 (3H, s), 2.16 (1H, dd), 2.37-2.43 (1H, m), 2.52-2.58 (1H, m), 3.11-3.14 (4H, m), 3.43-3.46 (4H, m), 3.68 (1H, dd), 3.74-3.79 (5H, s overlapping over m), 4.05 (1H, dd), 4.58 (2H, dd), 6.75 (2H, br s), 6.85 (1H, br d), 7.00 (1H, td), 7.04 (2H, d), 7.25-7.34 (2H, m), 7.76 (1H, s), 7.81 (2H, d) and 8.34 (1H, s).

Ethyl 4-(4-(4-hydroxy-3-methylphenyl)piperazin-1-yl)benzoate

A flask charged with a solution of ethyl 4-(piperazin-1-yl)benzoate (Xa) (20.0 g, 85.0 mmol) and 4-bromo-2-methylphenol (19.2 g, 102 mmol) in DMF (213 mL) was evacuated and backfilled with nitrogen three times. RuPhos G3 (1.43 g, 1.71 mmol) was added and the flask was evacuated and backfilled with nitrogen. The reaction mixture was cooled to 0° C. and LiHMDS (17.1 g, 102 mmol) was added. The reaction was stirred at RT for 10 min, then cooled in a water bath and LiHMDS (20.0 g, 120 mmol) added in equal portions (7×2.85 g) at 5 min intervals. The resulting solution was stirred at RT for 30 min and was then cooled to 0° C. and treated with 2M hydrochloric acid (200 mL) resulting in a pH of 6-7. The mixture was stirred for 15 min at RT and was then extracted with EtOAc (220 mL). The aq layer was separated and extracted with EtOAc (4×50 mL) and the combined organics were washed with brine (6×50 mL), and then dried and evaporated in vacuo to afford a cream solid. A mixture of isohexanes and IPA (1:1, 150 mL) was added and the suspension was stirred at RT for 30 min. The solid was collected by filtration, and the filter cake was washed with a mixture of isohexanes and IPA (1:1, 2×10 mL) followed by isohexanes (4×10 mL) and dried in vacuo at 40° C. for 18 hr to afford the title compound, intermediate (Villa), as a cream solid (15.3 g, 50%); R^(t) 2.29 min (Method b); m/z 341 (M+H)⁺ (ES⁺); ¹H NMR δ:1.29 (3H, t), 2.09 (3H, s), 3.06-3.09 (4H, m), 3.42-3.44 (4H, m), 4.24 (2H, dd), 6.66 (2H, br s), 6.76 (1H, br s), 7.03 (2H, d), 7.80 (2H, d), 8.72 (1H, s).

Ethyl 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydro furan-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoate

To a solution of intermediate (VIIIa) (15.3 g, 44.9 mmol) in DMF (110 mL) cooled to 0° C. was added sodium ethoxide (3.13 g, 46.1 mmol) and the mixture stirred at 0° C. for 10 min and then treated with the tosylate (IX) (20.2 g, 44.9 mmol). The reaction mixture was allowed to warm to RT, heated to 50° C. for 1 hr and then cooled to RT. Hydrochloric acid (1 M, 60 mL) and water (200 mL) were added and the mixture was stirred for 30 min at RT and then extracted with DCM (150 mL). The aq layer was separated and extracted with DCM (2×50 mL) and the combined organics were washed with brine (4×30 mL) and then dried and evaporated in vacuo to afford a cream solid. The solid was suspended in an equal mixture of isohexanes and IPA (80 mL) and stirred at RT for 1 hr. The solid was collected by filtration, washed with a mixture of iso-hexanes and IPA 1:1 (3×20 mL) and then dried in vacuo at 40° C. for 18 hr to afford the title compound, intermediate (IVb) as a white solid (16.4 g, 56%); R^(t) 2.92 min (Method b); m/z 618 (M+H)⁺ (ES⁺); ¹H NMR δ: 1.29 (3H, t), 2.10 (3H, s), 2.16 (1H, dd), 2.37-2.42 (1H, m), 2.52-2.58 (1H, m), 3.12-3.14 (4H, m), 3.43-3.46 (4H, m), 3.68 (1H, dd), 3.74-3.79 (2H, m), 4.05 (1H, dd), 4.24 (2H, dd), 4.58 (2H, dd), 6.76 (2H, br s), 6.86 (1H, br s), 6.98-7.05 (3H, m), 7.26-7.34 (2H, m), 7.77 (1H, s), 7.81 (2H, d), 8.34 (1H, s).

1-(((2R,4R)-4-((4-bromo-2-methylphenoxy)methyl)-2-(2,4-difluorophenyl)tetrahydro furan-2-yl)methyl)-1H-1,2,4-triazole

To a solution of 4-bromo-2-methyl phenol (920 mg, 4.89 mmol) in DMSO (10 mL) was added aq sodium hydroxide (0.39 mL, 12.5 M, 4.89 mmol) and the mixture stirred at RT for 10 min and then treated with the tosylate (IX) (2.00 g, 4.45 mmol). The reaction mixture was stirred at 60° C. for 72 hr then cooled to RT and partitioned between water (25 mL) and EtOAc (20 mL). The organic phase was separated and retained and the aq layer was extracted with EtOAc (3×25 mL). The combined organic extracts were washed with brine (3×15 mL) and then dried and evaporated in vacuo. The crude product was purified by flash column chromatography (SiO₂, 12 g, 0-30% EtOAc in DCM, gradient elution) to give the title compound, intermediate (XIII), as a colourless oil (1.84 g, 86%); R^(t) 2.78 min (Method a); m/z 464 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.09 (3H, s), 2.17 (1H, dd), 2.37-2.43 (1H, m), 2.52-2.60 (1H, m), 3.72-3.78 (2H, m), 3.82 (1H, dd), 4.00-4.06 (1H, m), 4.57 (2H, dd), 6.82 (1H, d), 7.00 (1H, td), 7.25-7.34 (4H, m), 7.76 (1H, s), 8.34 (1H, s).

Ethyl 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydro furan-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoate

A vial charged with ethyl 4-(piperazin-1-yl)benzoate (X) (103 mg, 0.44 mmol), intermediate (XIII) (170 mg, 0.37 mmol), RuPhos (8.5 mg, 18 μmol), RuPhos G3 (14.2 mg, 18 μmol) and cesium carbonate (191 mg, 0.59 mmol) was evacuated and backfilled with nitrogen three times before DMF (3.0 mL) was added. The mixture was heated at 80° C. for 18 h and then at 100° C. for 24 hr. The reaction mixture was cooled to RT and partitioned between water (10 mL) and EtOAc (10 mL). The organic phase was separated and retained and the aq layer was extracted with EtOAc (3×10 mL). The combined organics were washed with brine (3×10 mL) and then dried and evaporated in vacuo. The crude product was purified by flash column chromatography (SiO₂, 12 g, 0-100% EtOAc in isohexane, gradient elution) to give the title compound, intermediate (IVb), as a white solid (100 mg, 43%).

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoic acid

Hydrolysis of the Methyl Ester (IVa)

To a suspension of intermediate (IVa) (9.00 g, 14.9 mmol) in DMSO (370 mL) was added a solution of lithium hydroxide (1.79 g, 74.5 mmol) in water (37.0 mL). The mixture was heated at 70° C. for 22 hr and was then cooled to RT, diluted with water (1000 mL) and acidified (to pH 2) by the addition of 1M aq hydrochloric acid (80 mL). The mixture was cooled in an ice bath for 2 hr and the resulting precipitate was collected by filtration. The filter cake was washed with water (3×80 mL) and dried in vacuo at 50° C. to give the title compound, intermediate (II) as a white solid (4.66 g, 54%); R^(t) 2.21 min (Method 1a); m/z 590 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.10 (3H, s), 2.16 (1H, dd), 2.37-2.43 (1H, m), 2.52-2.58 (1H, m), 3.12-3.14 (4H, m), 3.42-3.45 (4H, m), 3.68 (1H, dd), 3.74-3.79 (2H, m), 4.05 (1H, dd), 4.58 (2H, dd), 6.76 (2H, br s), 6.86 (1H, br d), 6.97-7.03 (3H, m), 7.25-7.34 (2H, m), 7.77-7.80 (3H, m), 8.34 (1H, s) and 12.31 (1H, s).

Hydrolysis of the Ethyl Ester (IVb)

To a suspension of intermediate (IVb) (16.4 g, 26.6 mmol) in DMSO (375 mL) was added a solution of lithium hydroxide (3.18 g, 74.5 mmol) in water (50 mL). The mixture was heated at 70° C. for 22 hr and was then cooled to RT, poured into water (500 mL) and acidified (to pH 5-6) by the addition of 2M hydrochloric acid (70 mL). The mixture was stirred at RT for 30 min and the resulting solid was collected by filtration and washed with water (2×20 mL) and with diethyl ether (3×30 mL) and then dried in vacuo at 40° C. for 18 hr to afford the title compound, intermediate (II) as a tan solid (14.2 g, 84%); R^(t) 2.26 min (Method 1a); m/z 590 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.09 (3H, s), 2.16 (1H, dd), 2.37-2.42 (1H, m), 2.52-2.58 (1H, m), 3.12-3.14 (4H, m), 3.42-3.44 (4H, m), 3.68 (1H, dd), 3.74-3.79 (2H, m), 4.05 (1H, dd), 4.58 (2H, dd), 6.75 (2H, br s), 6.86 (1H, br s), 6.97-7.03 (3H, m), 7.26-7.34 (2H, m), 7.77-7.80 (3H, m), 8.34 (1H, s), 12.31 (1H, br s).

4-Bromo-N-(4-fluorophenyl)benzamide

To a solution of 4-fluoroaniline (III) (0.85 mL, 9.00 mmol), triethylamine (1.88 mL, 13.5 mmol) and DMAP (0.11 g, 0.90 mmol) in THF (15 mL) was added 4-bromobenzoyl chloride (XX) (2.37 g, 10.8 mmol). The reaction mixture was maintained at RT for 1 hr and was then partitioned between EtOAc (100 mL) and 1M hydrochloric acid (100 mL). The organic phase was separated and was washed sequentially with 1M hydrochloric acid (100 mL), sat. aq. NaHCO₃ (100 mL) and brine (100 mL) and then dried and evaporated in vacuo. The crude residue was triturated from warm DCM (100 mL) and the mixture was heated at reflux to give a white suspension which was allowed to cool to RT. The resulting precipitate was collected by filtration to afford the title compound, intermediate (XIX), as white solid (1.81 g, 65%); R^(t) 2.23 min; m/z 294/296 (M+H)⁺ (ES⁺); ¹H NMR δ: 7.20 (2H, t), 7.74-7.79 (4H, m), 7.90 (2H, d) and 10.36 (1H, s).

tert-Butyl 4-(4-((4-fluorophenyl)carbamoyl)phenyl)piperazine-1-carboxylate

A flask charged with tert-butyl piperazine-1-carboxylate (XII) (4.00 g, 215 mmol), intermediate (XIX) (6.63 g, 22.6 mmol), RuPhos (100 mg, 0.215 mmol) and RuPhos G3 (180 mg, 0.215 mmol) was evacuated and backfilled with nitrogen three times. A solution of LiHMDS (1M in THF, 75.0 mL, 75.0 mmol) was added and the reaction mixture was heated at 70° C. for 5 hr. After cooling to RT the mixture was partitioned between EtOAc (150 mL) and 1M hydrochloric acid (150 mL). The organic phase was separated and retained and the aq phase was extracted with EtOAc (3×150 mL). The combined organics were dried and concentrated in vacuo to afford a brown solid which was triturated in a mixture of isohexanes and diethyl ether (1:1, 100 mL). The product so obtained was collected by filtration, washed with a mixture of isohexanes and diethyl ether (1:1, 25 mL) and then dried in vacuo at 40° C. to provide the title compound, intermediate (XVIII) as a tan solid (6.44 g, 85%); R^(t) 2.40 min (Method a); m/z 400 (M+H)⁺; ¹H NMR δ: 1.43 (9H, s), 3.27-3.30 (4H, m), 3.45-3.48 (4H, m), 7.03 (2H, d), 7.14-7.18 (2H, m), 7.74-7.79 (2H, m), 7.88 (2H, d), 9.99 (1H, s).

N-(4-fluorophenyl)-4-(piperazin-1-yl)benzamide

To a solution of intermediate (XVIII) (6.44 g, 16.1 mmol) in DCM (200 mL) was added TFA (24.7 mL, 322 mmol). The reaction was stirred at RT for 2 hr and was then evaporated in vacuo. Toluene (5.0 mL) was added and the mixture was again evaporated in vacuo. The resulting oil was taken up in a mixture of DCM (90 mL) and methanol (10 mL) and was then extracted with a mixture of water (50 mL) and sat. aq NaHCO₃ (50 mL). The organic phase was separated and retained and the aq layer was extracted with a mixture of DCM and methanol (9:1, 3×100 mL). The combined organic layers were dried and concentrated in vacuo to afford the title compound, intermediate (XVII), as a brown solid (3.74 g, 70%); R^(t) 1.02 min (Method a); m/z 300 (M+H)⁺; ¹H NMR δ: 2.81-2.83 (4H, m), 3.18-3.20 (4H, m), 6.99 (2H, d), 7.14-7.18 (2H, m), 7.74-7.80 (2H, m), 7.85 (2H, d), 9.99 (1H, s).

N-(4-fluorophenyl)-4-(4-(4-methoxy-3-methylphenyl)piperazin-1-yl)benzamide

A flask charged with 4-bromo-1-methoxy-2-methylbenzene (XIVb) (406 mg, 2.02 mmol), intermediate (XVII) (550 mg, 1.84 mmol), RuPhos (43 mg, 0.092 mmol) and RuPhos G3 (77 mg, 0.092 mmol) was evacuated and backfilled with nitrogen three times. A solution of LiHMDS (9.2 mL, 1M in THF, 9.2 mmol) was added and the reaction mixture was heated at 70° C. for 8 hr. After cooling to RT the mixture was quenched by the addition of 1M aq. hydrochloric acid (9.0 mL) and then partitioned between water (15 mL) and EtOAc (15 mL). The organic layer was separated and retained and the aq layer was extracted with EtOAc (2×15 mL). The combined organics were washed with brine (20 mL) and then dried and evaporated in vacuo. The crude product so obtained was purified by flash column chromatography (SiO₂, 12 g, 0-100% EtOAc in isohexane, gradient elution) to afford a yellow solid. This material was repurified by flash column chromatography (SiO₂, 4 g, 0-10% EtOAc in DCM, gradient elution) to afford the title compound, intermediate (XVI), as an off-white solid (83 mg, 11%); R^(t) 2.27 min (Method a); m/z 420 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.13 (3H, s), 3.13-3.16 (4H, m), 3.42-3.45 (4H, m), 3.72 (3H, s), 6.77-6.88 (3H, m), 7.08 (2H, d), 7.17 (2H, t), 7.75-7.80 (2H, m), 7.89 (2H, d), 10.02 (1H, s).

N-(4-fluorophenyl)-4-(4-(4-hydroxy-3-methylphenyl)piperazin-1-yl)benzamide

To a suspension of intermediate (XVI) (83 mg, 0.20 mmol) in DCM (5.0 mL) at 0° C. was added a solution of boron tribromide (0.59 mL, 1M in DCM, 0.59 mmol). The reaction mixture was stirred at 0° C. for 30 min, allowed to warm to RT for 8 hr and was then partitioned between. water (15 mL) and DCM (10 mL). The organic layer was separated and retained and the aq layer was extracted with a mixture of DCM and MeOH (90:10, 5×15 mL). The combined organics were dried and evaporated in vacuo to give a crude product which was purified by flash column chromatography (SiO₂, 4.0 g, 0-3% MeOH in DCM, gradient elution) to afford the title compound, intermediate (XV), as a beige solid (61 mg, 72%); R^(t) 1.73 min (Method a); m/z 406 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.10 (3H, s), 3.08-3.11 (4H, m), 3.41-3.43 (4H, m), 6.67 (2H, br s), 6.77 (1H, br s), 7.07 (2H, d), 7.17 (2H, t), 7.76-7.80 (2H, m), 7.89 (2H, d), 8.73 (1H, s), 10.01 (1H, s).

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)-N-(4-fluorophenyl)benzamide

1. Preparation of Compound (I) from the Benzoic Acid Intermediate (II).

To a suspension of intermediate (II) (2.50 g, 4.24 mmol), EDCI (1.63 g, 8.48 mmol) and DMAP (30 mg, 0.21 mmol) in pyridine (30 mL) was added 4-fluoroaniline (0.41 mL, 4.3 mmol) and the reaction mixture heated at 60° C. for 2 hr and then cooled to RT. Dilution of the mixture with water (60 mL) and stirring for 5 min produced a solid, which was collected by filtration and then washed with water (3×10 mL) and with diethyl ether (2×15 mL) to give a tan coloured powder. The crude product so obtained was purified by flash column chromatography (SiO₂, 40 g, 0-3% MeOH in DCM, gradient elution) to afford Compound (I) as a yellow solid (2.47 g, 85%); R^(t) 2.60 min (Method a); m/z 683 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.10 (3H, s), 2.15 (1H, dd), 2.37-2.43 (1H, m), 2.53-2.58 (1H, m), 3.13-3.16 (4H, m), 3.42-3.44 (4H, m), 3.68 (1H, dd), 3.74-3.79 (2H, m), 4.05 (1H, dd), 4.58 (2H, dd), 6.76 (2H, br s), 6.86 (1H, br s), 6.99 (1H, td), 7.08 (2H, d), 7.16 (2H, t), 7.25-7.35 (2H, m), 7.76-7.80 (3H, m), 7.89 (2H, d), 8.34 (1H, s) and 10.00 (1H, s).

2. Preparation of Compound (I) from the Phenol Intermediate (XV)

To a solution of intermediate (XV) (19 mg, 0.047 mmol) in DMSO (1.5 mL) was added aq sodium hydroxide (1 M, 98 μL, 0.098 mmol). The mixture was stirred at RT for 10 min and then treated with a solution of tosylate (IX) (ex APIChem, Catalogue Number: AC-8330, 23.2 mg, 0.052 mmol) in DMSO (0.5 mL). The reaction mixture was stirred at 60° C. for 2 hr, cooled to RT and water (10 mL) was added. The resulting mixture was extracted with EtOAc (3×10 mL) and the combined organic extracts were dried and evaporated in vacuo to afford a brown oil. The crude product so obtained was purified by flash column chromatography (SiO₂, 4 g, 0-2% MeOH in DCM, gradient elution) to afford a beige solid (23 mg). The product was repurified by flash column chromatography (SiO₂, 4.0 g, 0-50% EtOAc in DCM, gradient elution) to afford Compound (I), as an off-white solid (14 mg, 42%); R^(t) 2.60 min (Method a); m/z 683 (M+H)⁺ (ES⁺).

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)-N-(4-fluorophenyl-2,3,5,6-d₄)benzamide

Preparation of a Tetra-deuterio Derivative of Compound (I)

To a suspension of intermediate (II) (200 mg, 0.34 mmol), EDCI (130 mg, 0.68 mmol) and DMAP (2.1 mg, 0.02 mmol) in pyridine (1.5 mL) was added a solution of 4-fluoroaniline-2,3,5,6-d₄ (43 mg, 0.37 mmol) in pyridine (0.5 mL) and the reaction mixture heated at 60° C. for 1 h. The reaction mixture was cooled to RT, diluted with water (10 mL) and stirred for 5 min, which produced a precipitate. The solid was collected by filtration, washed with water (3×2.0 mL) and then taken up in a mixture of DCM and MeOH (9:1, 5.0 mL). The mixture was passed through a phase separator and the organic solution was evaporated in vacuo to give a tan coloured solid (200 mg). The crude product so obtained was purified twice by flash column chromatography (SiO₂, 12 g, 0-2% MeOH in DCM, gradient elution; SiO₂, 40 g, 0-2.5% MeOH in DCM, gradient elution) to afford an off-white coloured powder.

The solid was suspended in DMSO (0.75 mL) and heated to 60° C. for 5 min until dissolution was complete. The resulting solution was cooled to RT and treated with water (1.0 mL) which gave a precipitate. The suspension was stirred at RT for 20 min and the solid was collected by filtration, rinsed with water (3×0.5 mL) and dried in vacuo at 50° C. or three days) to afford the title compound, (I) 4[²H] as a white solid (147 mg, 62%); R^(t) 2.59 min (Method 1a); m/z 687 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.10 (3H, s), 2.16 (1H, dd), 2.37-2.43 (1H, m), 2.52-2.60 (1H, m), 3.13-3.16 (4H, m), 3.42-3.44 (4H, m), 3.68 (1H, dd), 3.74-3.79 (2H, m), 4.05 (1H, dd), 4.58 (2H, dd), 6.76 (2H, br s), 6.86 (1H, br s), 7.00 (1H, td), 7.08 (2H, d), 7.25-7.35 (2H, m), 7.77 (1H, s), 7.89 (2H, d), 8.34 (1H, s) and 10.01 (1H, s).

Scale-up of the Preparation of Compound (I) by Route 2

The synthetic methodology described above for Route 2, (Scheme 1), has been successfully exploited to prepare the compound of the present invention on a scale of over 1.0 kg of API (Scheme 3). Two variants of the methodology have been developed in which the 4-piperazinyl benzoate [Intermediate (VIII)] comprises of either the ethyl ester (Villa) or the corresponding tert-butyl ester (VIIIb). Both of these compounds may be coupled with the tosylate (IX) to give the corresponding ester precursors to the benzoic acid (II). In the case of the ethyl ester the free acid is obtained by saponification, whilst the tert-butyl derivative is de-esterified by acidolysis. The procedures adopted for this synthetic campaign are depicted below and are described herein.

Analytical and Spectroscopic Methods

The analytical and spectroscopic methods pertaining to this experimental section are as set out below.

Reverse Phase HPLC Conditions for LCMS Analysis:

XBridge BEH Phenyl 4.6×150 mm column; 2.5 μm (Ex. Waters #186006720) at 40° C.; flow rate 1.0 mL·min⁻¹ eluted with a purified H₂O-MeCN gradient containing 0.1% formic acid over 25 min employing UV detection at 300 nm. Injection volume 5 μL. Gradient information: 0-2 min, held at 95% H₂O-5% MeCN; 2-15 min, ramped from 95% H₂O-5% MeCN to 10% H₂O-90% MeCN; 15-25 min, held at 10% H₂O-90% MeCN.

¹H NMR Spectroscopy:

¹H NMR spectra were collected using a JOEL ECX 400 MHz spectrometer. Residual undeuterated solvent was used as reference and, unless specified otherwise, samples were run in DMSO-d₆.

Ethyl 4-(4-(4-hydroxy-3-methylphenyl)piperazin-1-yl)benzoate

A solution of ethyl 4-(1-piperazinyl)benzoate (Xa) (500 g, 2.13 mol) and 4-bromo-2-methyl phenol (479 g, 2.56 mol) in anhydrous DMF (5.0 L) was degassed by placing the mixture alternately under vacuum and then a nitrogen atmosphere three times. The mixture was then treated with RuPhos G3 (35.7 g, 0.043 mol) and a solution of LiHMDS (1.0M in THF, 2560 mL, 2.56 mol) whilst maintaining the internal temperature below 35° C. (water bath cooling). A solution of LiHMDS (1.0M in THF) was then added in fourteen equal portions at two min intervals (14×213 mL, total 2.98 L, 2.98 mol) at 20-35° C. The resulting solution was stirred at 18-25° C. for 30 min after which analysis by HPLC indicated 0.6% of the ethyl 4-(1-piperazinyl) benzoate remained the reaction was deemed complete.

The reaction mixture was adjusted to pH 7.6 by the addition of 2M hydrochloric acid (5.50 L) whilst maintaining the temperature below 40° C., after which EtOAc (3.00 L) was added and the resulting phases separated. The aq phase was extracted with EtOAc (2×3.00 L and then 2×2.00 L) and the combined organics were washed with sat brine (8×1.00 L), dried over MgSO₄ and then evaporated in vacuo to give a light brown oily solid. The crude product was slurried in IPA (2.50 L) at 20-25° C. for 30 min and the resulting solid was collected by filtration. The filter cake was washed with IPA (2×500 mL) and pulled dry and the solids then dried under vacuum at 50° C. to provide the title compound, intermediate (Villa), as a light tan solid (380.0 g, 52%, HPLC purity 97.2%); R^(t) 11.01 min; m/z 341.3 (M+H)⁺ (ES⁺).

In order to control the level of palladium residues, the products from several batches were combined (1900 g, residual Pd 108 ppm), taken up into THF (19.0 L) and treated with MP-TMT resin (250 g) at 18-25° C. The mixture was stirred at this temperature for 24 hr and the resin was then removed by filtration and washed with THF (3.49 L). The filtrate was evaporated to dryness in vacuo and the resulting solid was slurried in IPA (4.75 L) at 18-25° C. for 1 hr and collected by filtration. The filter cake was washed with IPA (500 mL), pulled dry and was then dried in vacuo at 50° C. to give the title compound, intermediate (Villa), as an off-white solid (1789 g, 94%, residual Pd 17 ppm).

Ethyl 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)-tetrahydro furan-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoate

To a solution of intermediate (VIIIa) (1780 g, 5.23 mol) in anhydrous DMF (17.8 L) at 15-25° C. was added sodium ethoxide (391 g, 5.75 mol). After 45 min the tosylate (IX) (2586 g, 5.75 mol) was added in one portion and stirring was continued at 60-65° C. for 5 hr. Analysis by HPLC indicated that the reaction was essentially complete (1.67% starting material remaining). The mixture was cooled to 18-25° C. and the resulting suspension was treated with water (18.0 L) whist maintaining the temperature below 30° C. After cooling to 15-25° C. for 45 min the solid was collected by filtration and washed with water (2×7.14 L). The damp filter cake was slurried in ethanol (8.92 L) at reflux for 2 hr and the mixture was then cooled to 15-25° C. and stirred for 18 hr. The solids so obtained were collected by filtration, washed with ethanol (2×1.78 L) and then dried in vacuo at 50° C. to provide the title compound, intermediate (IVb), as an off-white solid (2855 g, 88%, HPLC purity 95.97%); R^(t) 14.99 min; m/z 618.5 (M+H)⁺ (ES⁺).

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)-tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoic acid mono-hydrochloride

To a suspension of intermediate (IVb) (1467 g, 2.38 mol) in mixture of DMSO (1.45 L) and water (5.90 L) at 18-25° C. was added a 50% w/w solution of KOH in water (2.93 L). The suspension was heated at 90-95° C. for 18 hr after which time HPLC analysis indicated that the reaction was complete (0.16% starting material remaining, 97.9% product). The reaction mixture was cooled to 40-50° C. and a mixture of IPA (14.9 L) and water (4.42 L) was added. After cooling to 15-25° C., the pH was adjusted to 1-2 by the addition of concentrated hydrochloric acid (3.12 L) whilst maintaining the internal temperature below 40° C. The resulting suspension was cooled to 15-25° C. and the solids were collected by filtration, pulled dry and then slurried in water (7.40 L) at 90-95° C. for 30 min. After cooling to 15-25° C., the solids were collected by filtration, washed with water (2×1.48 L) and pulled dry. Further drying in vacuo at 50° C. yielded the title compound, intermediate (II), as a white solid (1329 g, 89%, HPLC purity 99.0%; chlorine content: 6.61 w/w % [theory 5.66 w/w %]; R^(t) 12.92 min; m/z 590.4 (M+H)⁺ (ES⁺).

tert-Butyl 4-(4-(4-hydroxy-3-methylphenyl)piperazin-1-yl)benzoate

A solution of tert-butyl 4-(piperazin-1-yl)benzoate (Xb) (100 g, 381 mmol) and 4-bromo-2-methylphenol (85.5 g, 457 mmol) in anhydrous DMF (1.00 L) was degassed by placing the mixture alternately under vacuum and then a nitrogen atmosphere three times. Following this procedure, RuPhos G3 (6.38 g, 7.62 mmol) was added at 15-25° C. followed by a solution of LiHMDS in THF (1.06 M, 432. mL, 457 mmol) over 5 min whilst maintaining the temperature within 15-30° C., (water bath cooling). After stirring for 5 min additional aliquots of the solution of LiHMDS (1.06 M in THF) was added to the reaction mixture in fourteen equal portions (14×36 mL, total 504 mL, 533 mmol) at 2 min intervals, resulting in an exotherm from 16° C.-21° C. The reaction was stirred at 15-25° C. overnight (at which point HPLC showed the formation of 72.% of the desired product) and the pH of the mixture was adjusted to 7.3 by the addition of 2M hydrochloric acid (˜900 mL). The aq phase was separated and was extracted repeatedly with EtOAc (1.0 L, 500 mL and 2×250 mL). The combined organics were washed with brine (6×400 mL), dried over MgSO₄ and concentrated in vacuo to give a sticky yellow solid. The solid so obtained was suspended in IPA (500 mL) and was stirred at 15-25° C. for 1 hr. The suspension was filtered and the filter cake was washed with IPA (250 mL, 200 mL) and pulled dry. Further drying of the product in vacuo at 50° C. provided the title compound, intermediate (VIIIb) as an off-white solid (105.6 g, 75%, HPLC purity 97.1%); R^(t) 12.23 min; m/z 369.3 (M+H)⁺ (ES⁺)

tert-Butyl 4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)-tetra hydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoate

To a solution of intermediate (VIIIb) (100 g, 271 mmol) in DMF (500 mL) under a nitrogen atmosphere was added sodium ethoxide (22.2 g, 325 mmol) resulting in a mild exotherm (from 20 to 22.0° C.). After stirring at 15-25° C. for 45 min the reaction mixture was treated with the tosylate (IX) (146.4 g, 325 mmol) and was then heated at 60-65° C. for 2 hr. Analysis of the resulting mixture by HPLC indicated that the reaction was essentially complete (4.4% phenol remaining, 14.6% tosylate, 77.6% product) and the mixture was cooled to 40-45° C. and IPA (800 mL) was added. Water was then added drop-wise at 40-45° C. until a slight haze persisted (required 500 mL) at which point a small sample of the product (100 mg, 0.15 mmol) was added as a seed and the mixture stirred for 10 min at 40-45° C. to ensure precipitation was initiated. Water (500 mL) was added drop-wise at 40-45° C. and the suspension then cooled to 15-25° C. The resulting solid was collected by filtration, washed with water (3×200 mL) and then dried in vacuo at 50° C. give the crude product as an off-white solid (155.9 g, 89%, HPLC purity 94.8%). A portion of this material (85.0 g) was taken up in IPA (510 mL) by heating at 65-75° C. until dissolution was complete. The solution was then cooled to 15-25° C. and stirred for 30 min. The resulting solid was collected by filtration, washed with IPA (2×85 mL) and dried in vacuo at 50° C. to give the title compound, intermediate (IVc) as a white solid (83.4 g, 87% overall yield, HPLC purity 98.2%); R^(t) 15.74 min; m/z 646.6 (M+H)⁺ (ES⁺)

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)-tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)benzoic acid mono-hydrochloride

To a suspension of the tert-butyl benzoate (IVc) (83.4 g, 129 mmol) in a mixture of water (250 mL) and IPA (417 mL) was added a solution of conc hydrochloric acid (167 mL) in water (167 mL) whilst maintaining the internal temperature below 35° C. The resulting solution was then kept at 35° C. for 24 hr (solid formation observed after 2-3 hr) at which point HPLC analysis indicated the reaction was essentially complete (0.6% ester remaining, 98.1% product) The mixture was cooled to 15-25° C., IPA (417 mL) was added and the pH was adjusted ˜10 by the addition of aq NaOH (10 M, 200 mL) at <40° C. to give a solution. The pH was then re-adjusted to 1-2 by the addition of conc hydrochloric acid (25 mL) at <40° C. The resulting suspension was cooled to 15-25° C. and the solids were collected by filtration. The filter cake was resuspended in water (834 mL), heated to 80-85° C. and then stirred for 30 min. The suspension was then cooled to 15-25° C. and the solids collected by filtration, washed with water (2×83 mL) and dried in vacuo at 50° C. to provide the title compound, intermediate (II), (as the mono-hydrochloride salt) as a white solid (64.6 g, 80%, HPLC purity 97.6%); R^(t) 12.92 min; m/z 590.4 (M+H)⁺ (ES⁺).

4-(4-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)-tetrahydrofuran-3-yl)methoxy)-3-methylphenyl)piperazin-1-yl)-N-(4-fluorophenyl)benzamide

To a stirred suspension of the benzoic acid (II) as its mono-hydrochloride salt (1001 g, 1.60 mol) and HOBt.H₂O (216. g, 1.41 mol) in DMF (5020 mL) at <40° C. was added DIPEA (840 mL, 4.823 mol) followed by 4-fluoroaniline (181 mL, 1.91 mol) and then EDCI.HCl (368 g, 1.92 mol). The mixture was heated at 60-65° C. for 17 hr at which time analysis by HPLC indicated the reaction was complete (no starting material or reaction intermediate detected, 82.63% product). The resulting solution was cooled to 15-25° C. and was quenched with water (15.2 L) at <35° C., then cooled again to 15-25° C. and stirred for 1 hr The resulting solid was collected by filtration, washed with water (2×2.00 L) and pulled dry. The filter cake was re-slurried in water (5.00 L) at 15-25° C. for 45 min and the solids were collected by filtration, washed with water (2×2.00 L) and dried in vacuo to afford the title compound, Compound (I), as an off-white solid (1101 g, ˜100%, HPLC purity 95.8%); R^(t) 14.46 min; m/z 683.5 (M+H)⁺ (ES⁺); ¹H NMR δ: 2.10 (3H, s), 2.16 (1H, dd), 2.37-2.43 (1H, m), 2.50-2.58 (1H, m), 3.13-3.15 (4H, m), 3.41-3.44 (4H, m), 3.67 (1H, dd), 3.74-3.78 (2H, m), 4.05 (1H, t), 4.55 (1H, d), 4.61 (1H, d), 6.76 (2H, s), 6.86 (1H, s), 7.00 (1H, d, t), 7.08 (2H, d), 7.17 (2H, t), 7.26-7.35 (2H, m), 7.76-7.80 (2H, m), 7.77 (1H, s), 7.89 (2H, d), 8.35 (1H, s) and 10.02 (1H. S).

Biological Testing: Experimental Methods

Assessment of Planktonic Fungus Growth

a. Resazurin-Microtitre Assay

This assay was conducted using a modified, published method (Monteiro et al., 2012). Spores of Aspergillus fumigatus (NCPF2010, Public Health England, Wiltshire) were cultured in Sabouraud dextrose agar for 3 days. A stock spore suspension was prepared from a Sabouraud dextrose agar culture by washing with PBS-tween (10 mL; PBS containing 0.05% Tween-20, 100 U/mL Penicillin and 100 U/mL Streptomycin). The spore count was assessed using a Neubauer haemocytometer and, using PBS, adjusted to 10⁶ spores/mL. A working suspension of spores (10⁴ spores/mL) was prepared in filter sterilised MOPS RPMI-1640 (50 mL; RPMI-1640 containing 2 mM L-glutamine, 2% glucose and 0.165 M MOPS, buffered to pH 7 with NaOH). Resazurin sodium salt (100 μL of 1% solution; Sigma-Aldrich, Dorset, UK) was added to the spore suspension and mixed well. The spore suspension-resazurin mixture (100 μL/well) was added to 384-well plates (Catalogue number 353962, BD Falcon, Oxford, UK). Simultaneously, test compounds (0.5 μL DMSO solution) were added to 100 μL of the spore-resazurin mixture in quadruplicate to provide a final DMSO solution of 0.5% using an Integra VIAFLO 96 (Intergra, Zizers, Switzerland). For non-spore control wells, MOPS-RPMI-resazurin solution (100 μL) was added instead of the spore-resazurin mixture. The plate was covered with a Breathe Easier membrane (Catalogue No Z763624, Sigma-Aldrich, Dorset, UK), and incubated (35° C., 5% CO₂) until fluorescence in the inoculated wells was double that of the control wells (around 24 hr). The fluorescence of each well (545 nm (excitation)/590 nm (emission), gain 800, focal height 5.5 mm) was determined using a multi-scanner (Clariostar: BMG, Buckinghamshire, UK). The percentage inhibition for each well was calculated and the MIC₅₀, MIC₇₅ and MIC₉₀ values were calculated from the concentration-response curve generated for each test compound.

b. Broth Microdilution Assay

This assay was conducted using a modified method published by EUCAST (Rodriguez-Tudela et al., 2008). Spores of Aspergillus fumigatus (NCPF2010, NCPF7010 (Methionine 220 mutation), NCPF7099 (Glycine G54 mutation) from Public Health England, Wiltshire; TR34/L98H mutants from St Louis Hospital, Paris, France) were cultured in Sabouraud dextrose agar for 3 days. A stock spore suspension was prepared from a Sabouraud dextrose agar culture by washing with PBS-tween (10 mL; PBS containing 0.05% Tween-20, 100 U/mL Penicillin and 100 U/mL Streptomycin). The spore count was assessed using a Neubauer haemocytometer and then adjusted to 10⁶ spores/mL with PBS. A working suspension of spores (2×10⁵ spores/mL) was prepared in filter sterilised, BSA MOPS RPMI-1640 (50 mL; RPMI-1640 containing 2 mM L-glutamine, 0.5% BSA, 2% glucose, 0.165 M MOPS, buffered to pH 7 with NaOH). For the assay, BSA MOPS RPMI-1640 (50 μL/well) was added throughout the 384-well plate (Catalogue number 353962, BD Falcon, Oxford, UK) first. Test compounds (0.5 μL DMSO solution) were then added in quadruplicate using an Integra VIAFLO 96 (Integra, Zizers, Switzerland), and mixed well using a plate mixer. Subsequently 50 μL of the working spore suspension prepared above was added to all wells except non-spore control wells. For non-spore control wells, BSA MOPS-RPMI solution (50 μL/well) was added instead. The plate was covered with a plastic lid, and incubated (35° C. with ambient air) for 48 hr. The OD of each well at 530 nm was determined using a multi-scanner (Clariostar: BMG, Buckinghamshire, UK). The percentage inhibition for each well was calculated and the MIC₅₀, MIC₇₅ and MIC₉₀ values were calculated from the concentration-response curve generated for each test compound.

Fungus panel screening was conducted by Eurofins Panlabs Inc. The MIC and MIC₅₀ values of the test articles were determined following the guidelines of the Clinical and Laboratory Standards Institute, broth microdilution methods for yeast (CLSI M27-A2), (CLSI, 2002) and for filamentous fungi (CLSI M38-A), (CLSI, 2008).

Aspergillus fumigatus Infection of Bronchial Epithelial Cells

BEAS2B cells were seeded in 96-well plates (100 μL; 30,000 cells/well; Catalogue No 3596, Sigma Aldrich, Dorset, UK) in 10% FBS RPMI-1640 and were then incubated (37° C., 5% CO₂) for one day before experimentation. Test compounds (0.5 μL DMSO solution) or vehicle (DMSO) were added to each well to give a final DMSO concentration of 0.5%. BEAS2B cells were incubated with test compounds for 1 hr (35° C., 5% CO₂) before infection with Aspergillus fumigatus (20 μL; Public Health England) conidia suspension (0.5×10⁵/ml in 10% FBS RPMI-1640). The plate was incubated for 24 hr (35° C., 5% CO₂). Supernatant (50 μL) was collected and transferred to a PCR plate (Catalogue No L1402-9700, Starlab, Milton Keynes, UK), which was frozen (−20° C.) until use. After thawing, supernatant (5 μL) was diluted 1:20 by adding R7-PBS solution (95 μL; 1:4 R7 to PBS; Bio-Rad Laboratories, Redmond, Wash., USA). GM levels in these samples (50 μL) were measured using Platelia GM-EIA kits (Bio-Rad Laboratories, Redmond, Wash., USA). The percentage inhibition for each well was calculated and the IC₅₀ value was calculated from the concentration-response curve generated for each test compound.

Aspergillus fumigatus Infection of Human Alveoli Bilayers

In vitro models of human alveoli, consisting of a bilayer of human alveolar epithelial cells and endothelial cells, were prepared as previously described (Hope et al., 2007). This system allows administration of a test compound to the upper (“air” space) and/or lower (“systemic” space) compartments. This flexibility has been exploited to explore the effects of combination treatments by dosing Compound (I) to the upper chamber and posaconazole or other anti-fungal agents to the lower chamber. Primary human pulmonary artery endothelial cells (HPAEC) were harvested and diluted to 10⁶ cells/mL in EGM-2 media (Lonza, Basel, Switzerland). Transwells were inverted and the cell suspension (100 μL/well) was applied to the base of each transwell. The inverted transwells were incubated at RT within a flow hood for 2 hr after which they were turned upright. EGM-2 media was added to the lower (700 μL/well) and upper (100 μL/well) compartments and the transwells were incubated for 48 hr (37° C., 5% CO₂). The EGM-2 media in the lower compartment was then replaced with fresh EGM-2 media. A549 cells were harvested and diluted to 5×10⁵ cells/mL in 10% EBM, then added to the upper compartment (100 μL/well) of all transwells and the plates incubated for 72 hr (37° C., 5% CO₂). Conidia of Aspergillus fumigatus (the itraconazole sensitive strain NCPF2010 and the itraconazole resistant strain TR34-L98H) were cultured separately in Sabouraud dextrose agar for 3 days. A stock conidia suspension of either strain was prepared from a Sabouraud dextrose agar culture by washing with PBS-tween (10 mL; PBS containing 0.05% Tween-20, 100 U/mL Penicillin and 100 U/mL Streptomycin). The conidia count was assessed using a Neubauer haemocytometer and adjusted to 10⁶ conidia/mL with PBS. A working stock of conidia was prepared in EBM (conc of 10⁵ conidia/mL) immediately prior to use.

Test and reference compounds (or neat DMSO as the vehicle) were added to the appropriate wells of 24-well plates (3 μL/well containing 600 μL of 2% FBS EBM) for lower compartment treatment and to 96-well plates (1 μL/well containing 200 μL of 2% FBS EBM) for the treatment of the upper compartment, to provide a final DMSO concentration of 0.5%. The media in the upper compartment was aspirated and that containing the appropriate test and reference compounds, or vehicle, were added (100 μL/well). Transwells were then transferred into the 24-well plate containing the test and reference compounds or DMSO vehicle. After incubation for 1 hr (35° C., 5% CO₂) the conidia suspension (10 μL/well) was added to the upper compartment of each transwell. Plates were then incubated for 24 hr (35° C., 5% CO₂). Supernatants from each compartment (5 μL/compartment) were collected and stored (−20° C.). Media was replaced daily after collection of the supernatants and all wells were treated with test and reference compounds or with DMSO, as described above, for 3 days. Samples continued to be collected until fungal growth was visible by eye in all transwells. The levels of GM in the supernatant in lower compartment were then measured by ELISA (BioRad, CA, USA) as an index of Aspergillus fumigatus invasion.

Cell Viability: Resazurin Assay

BEAS2B cells were seeded in 384-well plates (100 μL; 3000/well/; BD Falcon, Catalogue No 353962) in RPMI-LHC8 (RPMI-1640 and LHC8 media combined in equal proportions) one day before experimentation. For cell-free control wells, RPMI-LHC8 (100 μL) was added. Test compounds (0.5 μL of a DMSO solution) were added to give a final DMSO concentration of 0.5% using an Integra VIAFLO 96 (Integra, Zizers, Switzerland). BEAS2B cells were incubated with each test compound for 1 day (37° C./5% CO₂ in RPMI-LHC8). After addition of resazurin stock solution (5 μL, 0.04%) the plates were incubated for a further 4 hr (37° C./5% CO₂). The fluorescence of each well at 545 nm (excitation) and 590 nm (emission) was determined using a multi-scanner (Clariostar: BMG Labtech). The percentage loss of cell viability was calculated for each well relative to vehicle (0.5% DMSO) treatment. Where appropriate, a CC₅₀ value was calculated from the concentration-response curve generated from the concentration-response curve for each test compound.

In Vivo Anti-Fungal Activity

Aspergillus fumigatus (ATCC 13073 [strain: NIH 5233], American Type Culture Collection, Manassas, Va., USA) was grown on Malt agar (Nissui Pharmaceutical, Tokyo, Japan) plates for 6-7 days at RT (24±1° C.). Spores were aseptically dislodged from the agar plates and suspended in sterile distilled water with 0.05% Tween 80 and 0.1% agar. On the day of infection, spore counts were assessed by haemocytometer and the inoculum was adjusted to obtain a concentration of 1.67×10⁸ spores mL⁻¹ of physiological saline.

To induce immunosuppression and neutropenia, A/J mice (males, 5 weeks old) were dosed with hydrocortisone (Sigma H4881; 125 mg/kg, sc) on days 3, 2 and 1 before infection, and with cyclophosphamide (Sigma C0768; 250 mg/kg, ip) 2 days before infection. On day 0, animals were infected with the spore suspension (35 μL intra-nasally).

Test compounds were administered intra-nasally (35 μL of a suspension of 0.08-2.00 mg/mL in physiological saline) once daily, 30 min before infection on day 0 and then on days 1, 2 and 3 (representing prophylactic treatment) or on days 1, 2 and 3 only (representing therapeutic treatment). For extended prophylactic treatment, test compounds (35 μL of a suspension of 0.0032 or 0.016 mg/mL in physiological saline) were administered intra-nasally once daily for seven days; then 30 min before infection on day 0, and thereafter, either on days 1, 2 and 3 after infection, or on day 0 only. The effects of these treatment paradigms were compared with those obtained when treatment was restricted to one day and 30 min before inoculation and then on days 1, 2 and 3 post infection; or reduced still further to one day and 30 min before infection only. Animal body weights were monitored daily and those exhibiting a reduction >20%, compared with their body weight on day 0, were culled.

Six hours after the last dose, animals were anesthetised, the trachea was cannulated and BALF was collected. The total number of alveolar cells was determined using a haemocytometer, and the numbers of alveolar macrophages and neutrophils were determined by FACS analysis (EPICS® ALTRA II, Beckman Coulter, Inc., Fullerton, Calif., USA) using anti-mouse MOMA2-FITC (macrophage) or anti-mouse 7/4 (neutrophil), respectively, as previously reported (Kimura et al., 2013). The levels of IFN-γ and IL-17 in BALF, and IL-6 and TNFα in serum were determined using Quantikine® mouse IFN-γ, IL-17, IL-6 or TNF-α ELISA kit (R&D systems, Inc., Minneapolis, Minn., USA) respectively. MDA, an oxidative stress marker, was assayed using OxiSelect® TBARS Assay Kits (MDA Quantitation; Cell Biolabs Inc, San Diego, Calif., USA). Aspergillus GM in serum was determination using Platelia GM-EIA kits (Bio-Rad Laboratories, Redmond, Wash., USA). Cut-off index was calculated by the formula: Cut-off index=OD in sample/OD in cut-off control provided in kit. For tissue fungal load assays, 100 mg of lung tissue was removed aseptically and homogenized in 0.2 mL of 0.1% agar in sterile distilled water. Serially diluted lung homogenates were plated on Malt agar plates (50 μL/plate), and incubated at 24±1° C. for 72 to 96 h. The colonies of A. fumigatus on each plate was counted and the fungal titre presented as CFU per gram of lung tissue.

Severely immunosuppressed, neutropenic A/J mice (males, 5 weeks old), which had been dosed with hydrocortisone (Sigma H4881; 125 mg/kg, sc) daily for three days before infection and with cyclophosphamide (Sigma C0768; 250 mg/kg, ip) two days before infection were used to evaluate the effects of the combined treatment of Compound (I) administered intranasally and posaconazole dosed orally. On day 0, animals were infected intranasally with 35 μL of the spore suspension (1.67×10⁸ spores/mL in physiological saline) of Aspergillus fumigatus (ATCC 13073 [strain: NIH 5233]). Compound (I) prepared as a suspension in isotonic saline (0.4 mg/mL) was dosed once daily by an intra-nasal injection (35 μL/mouse) on days 1-6 after infection. Posaconazole (1 mg/kg) was given orally once daily on days 1-6 after infection. Body weight and survival were monitored daily up to day 7.

Summary of Screening Results

Compound (I) demonstrates potent inhibitory activity against both azole sensitive Aspergillus fumigatus fungal growth, as evaluated by the resazurin assay, and fungal infection of bronchial epithelial cells (Table 2). In these assay systems Compound (I) showed significantly greater potency than voriconazole and amphotericin B, and similar potency to posaconazole. Incubation with Compound (I) had no or little effect on the viability of BEAS2B bronchial epithelial cells at concentrations up to, at least, 10 μM.

TABLE 2 The effects of treatment with Voriconazole, Posaconazole, Amphotericin B and Compound (I) on Aspergillus fumigatus (NCPF2010) planktonic fungal growth, on fungal infection of BEAS2B bronchial epithelial cells and on BEAS2B cell viability. MIC₅₀/MIC₇₅/CC₅₀ Values in assay system indicated (nM) Planktonic fungal Infection of BEAS2B Treatment growth¹ BEAS2B cells² Cell Viability³ (Test Compound) MIC₅₀ MIC₇₅ MIC₅₀ CC₅₀ Voriconazole 90.8 168 154 >28600 Posaconazole 3.64 6.94 4.48 >14300 Amphotericin B 28.5 64.4 nt 977 Compound (I) 1.98 5.02 5.43 >12200 Compound (I).4[²H] nt nt 3.15 >14600 Table Footnotes: ¹Resazurin-microtitre assay; ²Bronchial epithelial cells; ³n = 1-5;

Compound (I) also exhibits potent inhibitory activity against planktonic fungal growth as evaluated in a broth microdilution assay (Table 3). In this assay, Compound (I) showed significantly greater potency versus both posaconazole-resistant strains (NCPF7099, NCPF7100 and TR34/L98H) and a posaconazole-sensitive strain (NCPF2010) than posaconazole, voriconazole and Amphotericin B.

TABLE 3 The Effects of Treatment with Voriconazole, Posaconazole, Amphotericin B and Compound (I) on planktonic fungal growth of isolates of Aspergillus fumigatus. MIC₇₅ Values (nM) against the Treatment indicted Aspergillus fumigatus isolates¹ (Test Compound) NCPF2010 NCPF7099 NCPF7100 L98H Voriconazole 496 96.7 596 >2860 Posaconazole 15.3 112 71.5 150 Amphotericin B 382 365 >1080 209 Compound (I) 13.6 16.5 19.7 56.7 Compound (I).4[²H] 14.7 13.7 28.6 70.0 Table Footnotes: ¹Broth microdilution assay, n = 1-3

The effects of Compound (I) on the growth of wide range of fungal pathogens were evaluated using the CLSI broth microdilution methods. Compound (I) was found to be a potent inhibitor of the growth of Rhizopus oryzae, Cryptococcus neoformans, Chaectomimum globosum, Penicillium chrysogenum and Trichophyton rubrum as well as some Candida Spp (Table 4).

TABLE 4 The effects of Compound (I) on the growth of a range of fungi species. Compound (I) Voriconazole Posaconazole Fungal MIC₅₀ MIC₁₀₀ MIC₅₀ MIC₁₀₀ MIC₅₀ MIC₁₀₀ Agent Strain (μg/mL) (μg/mL) (μg/mL) Aspergillus ATCC204304 1.0 >8.0 1.0 2.0 0.063 0.13 flavus Aspergillus ATCC9348 >8.0 >8.0 >8.0 >8.0 0.25 1.0 pullulans Candida 20240.047 0.031 >8.0 0.031 >8.0 0.031 >8.0 albicans ATCC10231 0.13 >8.0 0.25 >8.0 0.13 >8.0 20183.073 0.5 >8.0 4.0 >8.0 0.25 >8.0 20186.025 >8.0 >8.0 >8.0 >8.0 >8.0 >8.0 Candida ATCC36583 0.5 >8.0 0.25 >8.0 0.5 >8.0 glabrata R363 0.5 >8.0 >8.0 >8.0 0.5 >8.0 Rhizopus ATCC11145 0.063 2.0 8.0 >8.0 0.13 >8.0 oryzae Cryptococcus ATCC24067 0.008 1.0 0.016 1.0 0.016 0.25 neoformans Chaetomium ATCC44699 0.063 >8.0 0.5 1.0 0.13 0.25 globosum Penicillium ATCC9480 0.031 >8.0 1.0 2.0 0.063 0.13 chrysogenum Trichophyton ATCC10218 <0.008 0.031 <0.008 0.063 <0.008 0.031 rubrum Table footnotes: MIC₅₀ /MIC₁₀₀ = concentration required for 50% and 100% inhibition of fungal growth by visual inspection (CLSI).

Monotherapy with either Compound (I) (0.1 μg/mL in the upper chamber) or posaconazole (0.01 μg/mL in the lower chamber) inhibited GM production on day 1 in human alveoli bilayers. However, the inhibitory effects of these treatments were lost rapidly thereafter (Table 5). In contrast, combination treatment of Compound (I) with posaconazole showed sustained inhibition of invasion post infection. Consequently, the DFB₅₀ for the combination treatment was 5.48 days, much longer than the values for either compound alone. This synergistic or additive effect of combination therapy was also confirmed when treatment with Compound (I) was combined with that of intraconazole, voriconazole or caspofungin (results not shown).

TABLE 5 Effects of Compound (I), Posaconazole and the treatment combination on Aspergillus fumigatus (NCPF2010) invasion into the lower chamber in human alveoli bilayers (transwells). GM Levels in the Lower Chamber for Treatments Indicated OD value (% inhibition vs.control)I Treatment Compound (I)¹ Posaconazole² Combination Day Vehicle Upper Chamber Lower Chamber Treatment 0 0 0 0 0 1 0.68 0.091 (86)   0.064 (91)   0.007 (99)  2 1.19 1.15 (3.4) 1.01 (15)  0.011 (99)  3 1.19 1.14 (3.7) 1.14 (4.1) 0.025 (98)  4 1.18 1.13 (4.5) 1.17 (1.1) 0.11 (91) 5 1.18 1.18 (0.3)   1.18 (−0.6) 0.42 (64) 6 1.18   1.18 (−0.3)   1.19 (−1.1) 0.73 (38) 7 1.18 1.16 (0.9) 1.17 (0.3)  1.15 (2.0) 8 1.16 1.13 (2.8) 1.15 (0.8)  1.12 (3.7) DFB₅₀ Values for 1.13 1.45 5.48 treatments indicated Table footnotes: ¹Dosed at 0.1 μg/mL; ²Dosed at 0.01 μg/mL; DFB₅₀: Days taken to reach a fungal burden of 50% of control

In addition, this combination treatment has been tested in bilayers infected with the azole resistant strain of Aspergillus fumigatus: TR34-L98H. (Table 6) Monotherapy with Compound (I) (1 μg/mL) in the upper chamber or with posaconazole (0.1 μg/mL) in the lower chamber showed limited benefit. In contrast, the combination of Compound (I) and posaconazole showed marked inhibitory effects on fungal invasion into the lower chamber. The beneficial effect of the combination treatment was observed on day 1 post infection, but disappeared after day 2.

TABLE 6 Effects of Compound (I), Posaconazole and the treatment combination on Aspergillus fumigatus (TR34-L98H strain) invasion into the lower chamber in the alveolar bilayer cell system (transwells). GM Levels in the Lower Chamber for Treatments Indicated OD value (% inhibition vs. control)I Compound (I)¹ Posaconazole² Combination Treatment Day Upper Chamber Lower Chamber Treatment 0 0 0 0 1 0.35 0.039 (88)     0.013 (96) 2 0.99   1.02 (−2.7) 0.082 (92) 3 0.99 0.97 (1.7)    0.54 (45) 4 1.01 1.02 (−1.4)   1.09 (−8.8) DFB₅₀ Values for 1.10 1.64 2.93 treatments indicated Table footnotes: ¹Dosed at 1 μg/mL; ²Dosed at 0.1 μg/mL; DFB₅₀: Days taken to reach a fungal burden of 50% of control

When given intranasally to immunocompromised, neutropenic mice, on days 0 and 1-3 following inoculation (Prophylactic Treatment) in a head-to-head comparison, Compound (I) showed superior effects to posaconazole on reducing body weight loss, measured over 3 days, caused by infection with Aspergillus fumigatus. (Table 7).

TABLE 7 Comparison of the Effects of Treatment with Compound (I) and Posaconazole on the body weight loss of immunocompromised, neutropenic mice caused by infection with Aspergillus fumigatus. Body weight loss caused by infection with A. fumigatus ² Drug (% Inhibition of weight loss) Treatment¹ Day 1 Day 2 Day 3 Vehicle plus Spores 9.2 ± 1.5 14.3 ± 1.9 19.3 ± 1.4 Posaconazole 7.3 ± 2.0 (21) 13.4 ± 1.9 (6) 18.1 ± 2.0 (6) Compound (I) 6.1 ± 1.8 (34)  8.7 ± 2.5 (39) 11.1 ± 5.6 (42) Table footnotes: ¹Dosed at 0.4 mg/mL intra-nasally; ²% weight loss compared with animal weight on day 0.

Furthermore, prophylactic and therapeutic treatment with Compound (I), showed superior effects to posaconazole on fungal load in the lung, as well as on GM concentrations in both BALF and serum, post infection. The data for Compound (I) used in prophylactic and therapeutic dosing regimens are shown in Table 8 and FIGS. 1, 2 and 3 (ID₅₀ values presented in Table 9).

TABLE 8 The Effects of Prophylactic and Therapeutic Treatment with Compound (I) on CFU in lung and galactomannan concentrations in BALF and serum in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice. Drug % Inhibition of response Treatment Conc CFU GM in BALF GM in serum Regimen (mg/mL) (/mg of lung) (COI) (COI) Vehicle + None 28.4 ± 16.9 4.8 ± 0.40 5.3 ± 1.1 Spores Compound (I): 0.08 15.2 ± 13.7 (46)  0.70 ± 0.39 (85) 0.81 ± 0.52 (85) Prophylactic 0.4 2.1 ± 1.6 (93) 0.37 ± 0.46 (92) 0.24 ± 0.18 (95) Treatment 2 0.8 ± 0.7 (97) 0.13 ± 0.02 (97) 0.18 ± 0.07 (97) Compound (I): 0.4 3.8 ± 1.0 (87) 0.24 ± 0.06 (95) 0.29 ± 0.11 (95) Therapeutic 2 1.9 ± 1.7 (93) 0.22 ± 0.14 (95) 0.25 ± 0.19 (95) Treatment 10 0.5 ± 0.3 (98) 0.11 ± 0.05 (98) 0.24 ± 0.11 (95) Table footnotes: The data for fungal load are shown as the mean ± standard error of the mean (SEM; n = 5-6).

TABLE 9 ID₅₀ values for Prophylactic Treatment with Posaconazole and Compound (I) on fungal load in the lung and on galactomannan concentrations in BALF and in serum, in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice. Drug substance (Prophylactic ID₅₀ Values for response indicated (mg/mL) Regimen) Lung Fungal Load GM in BALF GM in serum Compound (I) 0.086 <0.08 <0.08 Posaconazole 0.24 1.3 0.47

Prophylactic treatment with Compound (I), inhibited inflammatory cell accumulation in BALF (Table 10), in a similar fashion to posaconazole. In addition, prophylactic treatment with Compound (I) showed superior inhibitory effects to posaconazole versus IL-17, IFNγ and MDA concentrations in BALF, and the comparative ID₅₀ values for Compound (I) and for posaconazole in independent experiments are displayed in Table 11.

TABLE 10 The Effects of Prophylactic and Therapeutic Treatment with Compound (I) on macrophage and neutrophil accumulation into the BALF of Aspergillus fumigatus infected, immunocompromised, neutropenic mice. Cell numbers in BAL × 10⁵/mL Drug Conc (% inhibition) Treatment (mg/mL) Macrophage Neutrophil Vehicle + Spores 0.65 ± 0.14 0.49 ± 0.09 Compound (I) 0.08 0.40 ± 0.15 (38) 0.37 ± 0.04 (24) Prophylactic 0.4 0.32 ± 0.07 (51) 0.26 ± 0.12 (47) Treatment 2 0.26 ± 0.05 (60) 0.22 ± 0.04 (55) Compound (I) 0.4 0.43 ± 0.05 (34) 0.38 ± 0.04 (22) Therapeutic 2 0.40 ± 0.11 (38) 0.34 ± 0.05 (31) Treatment 10 0.32 ± 0.07 (51) 0.27 ± 0.08 (45) Table footnotes: The data for cell number are shown as the mean ± standard error of the mean (SEM), N = 5-6.

TABLE 11 ID₅₀ values for Prophylactic Treatment with Posaconazole and Compound (I) on IL-17, IFNγ and MDA levels in BALF in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice. Drug substance ID₅₀ Values for (Prophylactic biomarkers indicated (mg/mL) Regimen) IL-17 IFNγ MDA Compound (I) 0.074 <0.08 0.11 Posaconazole 0.61 0.22 0.69

Furthermore, data showing the effects of Compound (I) on IFNγ, IL-17 and MDA levels in the BALF, when administered either prophylactically or therapeutically, are shown in Table 12 and the effects on serum, IL-6 and TNFα are shown in Table 13.

TABLE 12 The Effects of Prophylactic and Therapeutic Treatment with Compound (I) on IFNγ, IL-17 and MDA levels in the BALF of Aspergillus fumigatus infected, immunocompromised, neutropenic mice. Biomarker Concentrations in BALF (% Inhibition) Treatment Drug Conc IFNγ IL-17 MDA Regimen (mg/mL) (pg/mL) (pg/mL) (μg/mL) Vehicle + Spores 9.2 ± 1.0 19.8 ± 3.6 1.8 ± 0.2 Compound (I) 0.08 3.7 ± 1.7 (60) 9.8 ± 5.3 (51) 0.96 ± 0.32 (47) prophylactic 0.4 3.0 ± 0.8 (67) 6.7 ± 4.9 (66) 0.57 ± 0.22 (68) 2 2.5 ± 0.3 (73) 3.2 ± 0.8 (84) 0.34 ± 0.05 (81) Compound (I) 0.4 4.3 ± 2.2 (53) 8.5 ± 2.9 (57) 0.45 ± 0.10 (75) therapeutic 2 3.3 ± 0.8 (64) 4.0 ± 0.8 (80) 0.37 ± 0.10 (79) 10 2.1 ± 0.3 (77) 2.9 ± 0.7 (85) 0.25 ± 0.05 (86) Table footnotes: The data for biomarker concentrations are shown as the mean ± standard error of the mean (SEM), N = 5-6.

TABLE 13 The Effects of Prophylactic and Therapeutic Treatment with Compound (I) on IL-6 and TNFα levels in the serum of Aspergillus fumigatus infected, immunocompromised, neutropenic mice Conc of Biomarkers (pg/mL) Treatment Drug Conc (% Inhibition) Regimen (mg/mL) IL-6 TNFα Vehicle + Spores 284 ± 112 25.6 ± 8.0 Compound (I) 0.08  159 ± 73.3 (44) 11.8 ± 5.9 (54)  Prophylactic 0.4 86.3 ± 46.9 (70) 7.3 ± 3.5 (71) Treatment 2 44.5 ± 12.2 (84) 4.7 ± 0.4 (82) Compound (I) 0.4 51.7 ± 16.8 (82) 6.2 ± 0.5 (76) Therapeutic 2 44.2 ± 11.4 (84) 5.5 ± 0.7 (79) Treatment 10 35.9 ± 10.4 (87) 4.9 ± 0.6 (81) Table footnotes: The data for biomarker concentrations are shown as the mean ± standard error of the mean (SEM), N = 5-6.

Therapeutic treatment with Compound (I) was also found to maintain potent inhibition of lung fungal load, serum galactomannan levels and on BALF cytokine concentrations in Aspergillus fumigatus infected, immunocompromised, neutropenic mice. (Tables 7, 8 9 and 10 and FIGS. 1, 2 and 3).

The effects of extended prophylactic dosing with Compound (I) on biomarkers in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice were also evaluated. Extended prophylaxis with Compound (I) was found to inhibit fungal load in the lung, as well as the GM concentrations in both BALF and serum, at 25 fold lower doses than those used in a previous biomarker study (Table 14). Furthermore, the data suggest an accumulation of anti-fungal effects in the lung on repeat dosing since seven days of prophylaxis produced greater anti-fungal effects than did prophylactic treatment for a single added day. The compound's persistence of action in the lung is suggested by the finding that treatment on days −7 to day 0 generated superior anti-fungal effects on day 3 than those resulting from treatment on days −1 and 0, only. Nevertheless this abbreviated dosing protocol was still protective

TABLE 14 Effects of extended prophylactic dosing of Compound (I) on fungal load (CFU) in lung and GM concentrations in BALF and serum in Aspergillus fumigatus infected, immuno-compromised, neutropenic mice. Treatment Dose of Values and % Inhibition of response³ Regimen¹ Compound (I) CFU GM in BALF GM in Serum (Days dosed) (μg/mL) (/mg of lung) (COI) (COI) Vehicle plus None 34.7 ± 10.7 5.1 ± 0.9 4.3 ± 1.0 Spores² −7 to +3 3.2 8.3 ± 2.0 (76) 2.6 ± 0.36 (49) 1.8 ± 0.43 (58) −1 to +3 3.2 9.5 ± 3.3 (73) 2.8 ± 0.71 (45) 2.2 ± 0.69 (49) −7 to +3 16 5.0 ± 2.3 (86) 1.7 ± 0.39 (67) 1.4 ± 0.20 (67) −1 to +3 16 6.1 ± 2.8 (82) 2.2 ± 0.61 (57) 1.6 ± 0.41 (63) −7 to 0   16 6.7 ± 1.7 (81) 2.3 ± 0.52 (55) 1.7 ± 0.59 (60) −1, 0 16 13.1 ± 2.6 (62)  4.5 ± 0.50 (12) 4.0 ± 0.88 (7)  Table footnotes: ¹The N value was six for all drug treated groups; ²The N value was five for the vehicle treated group; ³The data for fungal load and GM levels are shown as the mean ± standard error of the mean and the percentage inhibition, with respect to vehicle.

The influence on survival of combining the treatments of Compound (I), dosed topically, with oral Posaconazole, was evaluated in severely immuno-compromised, neutropenic mice after inoculation with Aspergillus fumigatus. Monotherapy with Compound (I) (0.4 mg/mL, given intranasally) or with Posaconazole (1.0 mg/kg, dosed orally) showed only a very limited therapeutic benefit. In contrast, the combination of Compound (I) and Posaconazole demonstrated a marked increase on survival time following infection (Table 15).

TABLE 15 Effects of Compound (I) and Posaconazole as monotherapy or in combination on survival in severely immune-compromised, neutropenic mice infected with Aspergillus fumigatus. No. of survivors Median Log-rank test Treatment on day 7 survival for survival Regimen Dose (Route) (%) (days) (vs. infection) Vehicle none 0/6 (0) 5 — Compound (I) 0.4 mg/mL (in) 0/6 (0) 6 p < 0.05 Posaconazole 1 mg/kg, (po) 0/6 (0) 6.5 Not significant Compound (I) 0.4 mg/mL (in)  5/6 (83) Undefined p < 0.001 plus 1 mg/kg (po) Posaconazole Table footnotes: N = 8 per group.

In Vivo Pharmacokinetics

It is a commonly used procedure for pulmonary, therapeutic agents to be dosed into the lungs of animals, for example mice, and plasma collected at various time points after dosing in order to characterise the resulting systemic exposure to the administered compound. The compound of the invention may be tested in such in vivo systems.

Summary of the Biological Profile of Compound (I)

Compound (I) has been found to be a potent inhibitor of Aspergillus fumigatus planktonic growth and bronchial epithelial cell infection. Compound (I) also inhibited the growth of posaconazole-resistant and voriconazole-resistant Aspergillus fumigatus isolates, demonstrating greater potency than posaconazole, voriconazole and intraconazole against these strains. Compound (I) was also found to be a potent inhibitor of the growth of Rhizopus oryzae, Cryptococcus neoformans, Chaetomimum globosum, Penicillium chrysogenum and Trichophyton rubrum as well as some Candida Spp. In an in vitro model of alveoli, Compound (I) showed impressive activity against Aspergillus invasion, both as monotherapy and when dosed in combination with posaconazole. In vivo, in Aspergillus fumigatus infected, immunocompromised, neutropenic mice, Compound (I), demonstrated potent inhibition of Aspergillus fumigatus infection, as well as the associated lung immune response whether dosed prophylactically or as a treatment. Compound (I) was also highly efficacious in reducing infection-dependent body weight loss. These inhibitory effects were superior to those of posaconazole. It is significant that the beneficial anti-fungal effects of Compound (I) are observed in both a prophylactic and a therapeutic setting.

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Throughout the specification and the claims which follow, unless the context requires otherwise, the word ‘comprise’, and variations such as ‘comprises’ and ‘comprising’, will be understood to imply the inclusion of a stated integer, step, group of integers or group of steps but not to the exclusion of any other integer, step, group of integers or group of steps. 

The invention claimed is:
 1. A compound of formula (XIII):

or a salt thereof.
 2. A process for preparing a compound of formula (II)

or a salt thereof; which comprises reacting a compound of formula (XIII):

or a salt thereof; with a compound of formula (X):

wherein R^(a) represents C₁₋₅ alkyl; or a salt thereof; to give a compound of formula (IV)

wherein R^(a) represents C₁₋₅ alkyl; or a salt thereof; followed by hydrolysis of the compound of formula (IV) to give said compound of formula (II). 